extrusion_corner_bracket_assembly() and extrusion_inner_corner_bracket() can now be passed the extrusion type.

E2020t and E4040t thinner extrusions added to work with the brackets.
Extrusions can now have recessed channels, round or square centre sections and holes.
Fixed the shape of extrusion centre section spars.
T-nuts now have 45 degree chamfers instead of a fixed 1mm minimum thickness.

CHANGELOG.md

@@ -3,9 +3,244 @@
 This changelog is generated by `changelog.py` using manually added semantic version tags to classify commits as breaking changes, additions or fixes.
 
 
+### [v15.24.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.24.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.23.0...v15.24.0 "diff with v15.23.0")
+*   2021-08-31 [`d9af5b7`](https://github.com/nophead/NopSCADlib/commit/d9af5b7f705791ca8ef230ecd1b831c042587002 "show commit") [C.P.](# "Chris Palmer") Updated images and readme.
+
+*   2021-08-31 [`9d65f69`](https://github.com/nophead/NopSCADlib/commit/9d65f69bf3e7cd325d24bc5410a4763bb7164b8f "show commit") [M.B.](# "Martin Budden") Added `M2p5_dome_screw`.
+
+### [v15.23.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.23.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.22.0...v15.23.0 "diff with v15.22.0")
+*   2021-08-31 [`00c5c90`](https://github.com/nophead/NopSCADlib/commit/00c5c90a5e74f47f0e6f5e3a7996f70fa34f0833 "show commit") [C.P.](# "Chris Palmer") Updated big picture
+
+*   2021-08-31 [`01c26d8`](https://github.com/nophead/NopSCADlib/commit/01c26d8a349e802738a8b0d06575a3e6915bf070 "show commit") [C.P.](# "Chris Palmer") Added Lichuan servo motors contributed by Niclas Hedhman.
+
+*   2021-08-31 [`ef21024`](https://github.com/nophead/NopSCADlib/commit/ef2102420b15e5be4008a6a3cecf5416857265f9 "show commit") [C.P.](# "Chris Palmer") Added NEMA8 and NEMA8BH stepper motors.
+Steppers can now have dual shafts, hollow shafts and black end caps.
+
+*   2021-08-31 [`540f841`](https://github.com/nophead/NopSCADlib/commit/540f84116355e7f44a9b5796816d1e3422128ff3 "show commit") [C.P.](# "Chris Palmer") Added crude representation of JST ZH connectors.
+
+*   2021-08-31 [`1045502`](https://github.com/nophead/NopSCADlib/commit/1045502efb1cb94fb7bcc11fd4483b425a880926 "show commit") [C.P.](# "Chris Palmer") Added more aluminium sheet thickness
+
+*   2021-08-31 [`485184f`](https://github.com/nophead/NopSCADlib/commit/485184f09213ff0b191d5c8339471cd24ba3cc90 "show commit") [C.P.](# "Chris Palmer") Added HGH15CA and HGH20CA rails.
+
+*   2021-08-31 [`b893c90`](https://github.com/nophead/NopSCADlib/commit/b893c9069a6bae762733cf1e139d49bab28ad792 "show commit") [C.P.](# "Chris Palmer") Added SFU1610 ballscrew nut
+
+*   2021-08-31 [`69f4ced`](https://github.com/nophead/NopSCADlib/commit/69f4ced29da7e37c88ca24b924c6430144eec849 "show commit") [C.P.](# "Chris Palmer") Added `M8_cs_cap_screw,` `M5_grub_screw` and `M6_grub_screw`.
+Fixed `M6_cs_cap_screw` and `M4_grub_screw` socket sizes.
+
+*   2021-08-31 [`5c1aa84`](https://github.com/nophead/NopSCADlib/commit/5c1aa849fe5992617c3128c47dfc969504cbfd2f "show commit") [C.P.](# "Chris Palmer") New layout for big picture.
+
+### [v15.22.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.22.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.21.1...v15.22.0 "diff with v15.21.1")
+*   2021-08-27 [`1247303`](https://github.com/nophead/NopSCADlib/commit/1247303cb9dc2694994993b5dc046683becb7fde "show commit") [C.P.](# "Chris Palmer") Updated images and readme.
+
+*   2021-08-13 [`14ab1bb`](https://github.com/nophead/NopSCADlib/commit/14ab1bb8b614055e0bf4ad33799276b0017ca13e "show commit") [M.B.](# "Martin Budden") Added Raspberry Pi Pico.
+
+#### [v15.21.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.21.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.21.0...v15.21.1 "diff with v15.21.0")
+*   2021-08-09 [`be53547`](https://github.com/nophead/NopSCADlib/commit/be53547728834d8e786ad4cb5637c768320a3105 "show commit") [M.B.](# "Martin Budden") Fixed display of BLDC prop shaft when thread length `=` 0.
+
+*   2021-07-04 [`ba7d7d3`](https://github.com/nophead/NopSCADlib/commit/ba7d7d32adf554d163143c0ae1707565340bb35b "show commit") [C.P.](# "Chris Palmer") Updated chnagelog.
+
+### [v15.21.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.21.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.20.0...v15.21.0 "diff with v15.20.0")
+*   2021-07-01 [`df35e14`](https://github.com/nophead/NopSCADlib/commit/df35e14fc71794c3826d6c99ce3cab93a4cfa5fe "show commit") [M.B.](# "Martin Budden") Improved handling of pcb plating colour.
+
+### [v15.20.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.20.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.19.3...v15.20.0 "diff with v15.19.3")
+*   2021-06-29 [`c982876`](https://github.com/nophead/NopSCADlib/commit/c982876ebc0f95b466de1af3c80642dfd88800e6 "show commit") [C.P.](# "Chris Palmer") Can now specify the screw used for PSU shrouds and get the wall thickness.
+
+#### [v15.19.3](https://github.com/nophead/NopSCADlib/releases/tag/v15.19.3 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.19.2...v15.19.3 "diff with v15.19.2")
+*   2021-06-17 [`92d0444`](https://github.com/nophead/NopSCADlib/commit/92d0444e5f96c8f4768afb3d014044d7e66c6e69 "show commit") [C.P.](# "Chris Palmer") Changelog now runs codespell to fix the spellings in the commit comments.
+
+#### [v15.19.2](https://github.com/nophead/NopSCADlib/releases/tag/v15.19.2 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.19.1...v15.19.2 "diff with v15.19.1")
+*   2021-06-15 [`8d7c44b`](https://github.com/nophead/NopSCADlib/commit/8d7c44b80deffcc8c6b84c7a6485c959826cb381 "show commit") [M.B.](# "Martin Budden") Spelling corrections.
+
+#### [v15.19.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.19.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.19.0...v15.19.1 "diff with v15.19.0")
+*   2021-06-17 [`d38055c`](https://github.com/nophead/NopSCADlib/commit/d38055c15c8b00f91f9c5a4749264acc9b123aad "show commit") [C.P.](# "Chris Palmer") Updated readme.
+
+*   2021-06-11 [`dcfe426`](https://github.com/nophead/NopSCADlib/commit/dcfe4262c519fb750702564309b790cda5b1c090 "show commit") [M.B.](# "Martin Budden") Fixed typos.
+
+### [v15.19.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.19.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.18.0...v15.19.0 "diff with v15.18.0")
+*   2021-06-17 [`c7a6d81`](https://github.com/nophead/NopSCADlib/commit/c7a6d8164f545e83c4d871080ac63b7d903829df "show commit") [C.P.](# "Chris Palmer") Added `molex_usb_Ax1()` and now shows SMT caps in the PCB test.
+
+### [v15.18.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.18.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.17.1...v15.18.0 "diff with v15.17.1")
+*   2021-06-08 [`d1a17bd`](https://github.com/nophead/NopSCADlib/commit/d1a17bd4ac90a7d3d6de7c4d4d032e8198c48647 "show commit") [C.P.](# "Chris Palmer") Added LIPO fuel gauge PCB.
+
+*   2021-06-08 [`b8efa11`](https://github.com/nophead/NopSCADlib/commit/b8efa11fd9504f4b837be663190d238c6227941e "show commit") [C.P.](# "Chris Palmer") Added SMD capacitors.
+
+*   2021-06-07 [`3bc8f35`](https://github.com/nophead/NopSCADlib/commit/3bc8f35e37741ef12d45951546059902b472b34a "show commit") [C.P.](# "Chris Palmer") Can now put `jst_ph` connectors on PCBs
+
+*   2021-06-07 [`39c11ef`](https://github.com/nophead/NopSCADlib/commit/39c11ef3b209256be393b3b211fef72c8ac793a1 "show commit") [C.P.](# "Chris Palmer") Added 2p54joiner to represent cropped headers joining PCBs.
+
+*   2021-06-07 [`5a8a1da`](https://github.com/nophead/NopSCADlib/commit/5a8a1da8801e3d799b7e322b397b236685552f97 "show commit") [C.P.](# "Chris Palmer") Added Seeeduino XIAO.
+Tiny PCBs now shown in a third line.
+
+*   2021-06-07 [`3147862`](https://github.com/nophead/NopSCADlib/commit/3147862212d6d1277a5e164909e4004e3e321f10 "show commit") [C.P.](# "Chris Palmer") PCB lands can be rounded and can specify colour.
+Holes can be positioned on the edge to make surface mountable connections.
+
+#### [v15.17.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.17.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.17.0...v15.17.1 "diff with v15.17.0")
+*   2021-06-07 [`4fc8a7f`](https://github.com/nophead/NopSCADlib/commit/4fc8a7f47df9a880b8e02c9e0f1a3a63d9939c3e "show commit") [C.P.](# "Chris Palmer") Fixed z-fighting between transparent LEDs and PCB.
+
+### [v15.17.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.17.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.16.2...v15.17.0 "diff with v15.16.2")
+*   2021-06-06 [`a9ed994`](https://github.com/nophead/NopSCADlib/commit/a9ed9944c328d1fa5121ae10e4e0243bda45f001 "show commit") [C.P.](# "Chris Palmer") Added PERF70x51.
+
+*   2021-06-06 [`9cd2dbc`](https://github.com/nophead/NopSCADlib/commit/9cd2dbc3167c1d14ac1f72e5676f4154151b5638 "show commit") [C.P.](# "Chris Palmer") Added copper colour constant.
+Copper PCB pads and veroboard tracks now use copper colour.
+
+#### [v15.16.2](https://github.com/nophead/NopSCADlib/releases/tag/v15.16.2 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.16.1...v15.16.2 "diff with v15.16.1")
+*   2021-06-06 [`f3bfbbf`](https://github.com/nophead/NopSCADlib/commit/f3bfbbfcf21209fd993aa7ebc25c8d8d3c12fbd5 "show commit") [C.P.](# "Chris Palmer") Fixed Python error when top level assembly is empty.
+
+*   2021-06-06 [`baaa85f`](https://github.com/nophead/NopSCADlib/commit/baaa85ffedb1a7cdca42e01ca8f2e257438070fc "show commit") [C.P.](# "Chris Palmer") Updated readme.
+
+*   2021-06-06 [`f1a49d4`](https://github.com/nophead/NopSCADlib/commit/f1a49d4e28bf063950b113c64acaa918d470767f "show commit") [C.P.](# "Chris Palmer") Better description of `pcb_grid()`.
+
+#### [v15.16.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.16.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.16.0...v15.16.1 "diff with v15.16.0")
+*   2021-06-04 [`9a4cc7e`](https://github.com/nophead/NopSCADlib/commit/9a4cc7ec42bf440e24ad3dacd88d7055736ae793 "show commit") [C.P.](# "Chris Palmer") Ziptie BOM entries no longer segregated by radius wrapped around.
+
+### [v15.16.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.16.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.15.0...v15.16.0 "diff with v15.15.0")
+*   2021-06-04 [`a782d43`](https://github.com/nophead/NopSCADlib/commit/a782d43e67f4091f44bd9018817e7263e2944477 "show commit") [C.P.](# "Chris Palmer") `bom.py` now generates `bom.csv` to allow costed BOMs to be made using a spreadsheet.
+
+### [v15.15.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.15.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.14.2...v15.15.0 "diff with v15.14.2")
+*   2021-06-03 [`823f3b9`](https://github.com/nophead/NopSCADlib/commit/823f3b936e6c33897445d3f3272b69237f013537 "show commit") [C.P.](# "Chris Palmer") Add the ability to have a target specific top level module in place of `main_assembly()`.
+
+#### [v15.14.2](https://github.com/nophead/NopSCADlib/releases/tag/v15.14.2 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.14.1...v15.14.2 "diff with v15.14.1")
+*   2021-06-02 [`749a1f0`](https://github.com/nophead/NopSCADlib/commit/749a1f0648196bd0ae47dbe93ac1b5e3a06d78cd "show commit") [C.P.](# "Chris Palmer") Fixed male thread z-fighting bug.
+
+*   2021-06-01 [`5c898df`](https://github.com/nophead/NopSCADlib/commit/5c898df2172a7e202c9e3d8c6641a0aaf95e5d48 "show commit") [C.P.](# "Chris Palmer") More readable code in `rounded_polygon`.
+
+#### [v15.14.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.14.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.14.0...v15.14.1 "diff with v15.14.0")
+*   2021-06-01 [`20d799a`](https://github.com/nophead/NopSCADlib/commit/20d799a3c115d3d32f101c4419d6e9b57c3be8c7 "show commit") [C.P.](# "Chris Palmer") `IEC_320_C14_switched_fused_inlet` now shows the correct object name in the example.
+
+### [v15.14.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.14.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.13.4...v15.14.0 "diff with v15.13.4")
+*   2021-05-31 [`2581098`](https://github.com/nophead/NopSCADlib/commit/258109811b7b7f71895340dc4b86b96d7dbc2037 "show commit") [C.P.](# "Chris Palmer") Added uppercase version of `BLCD_motors.scad`.
+
+*   2021-05-31 [`b39fd53`](https://github.com/nophead/NopSCADlib/commit/b39fd536c2841a95ab50b8a196e21ee8fc5976d1 "show commit") [C.P.](# "Chris Palmer") Removed lower case version of `bldc_motors.scad`.
+
+*   2021-05-31 [`a5a87d2`](https://github.com/nophead/NopSCADlib/commit/a5a87d260dd4bbe40a8727a4099207271918d02b "show commit") [C.P.](# "Chris Palmer") Updated images and readme.
+
+*   2021-05-30 [`00ca412`](https://github.com/nophead/NopSCADlib/commit/00ca412441c85ea1fd7082453c823445fbbdce4e "show commit") [M.B.](# "Martin Budden") Added BLDC3548 motor.
+
+*   2021-05-30 [`1e6d7f5`](https://github.com/nophead/NopSCADlib/commit/1e6d7f5dd68e64181aef019bb8bca186abb2ac68 "show commit") [M.B.](# "Martin Budden") Brushless DC motors.
+
+#### [v15.13.4](https://github.com/nophead/NopSCADlib/releases/tag/v15.13.4 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.13.3...v15.13.4 "diff with v15.13.3")
+*   2021-05-30 [`ec07d95`](https://github.com/nophead/NopSCADlib/commit/ec07d95657d52aab375b3b2acb95c87b369d2194 "show commit") [M.B.](# "Martin Budden") Added assertion to check colour format in module thread.
+
+#### [v15.13.3](https://github.com/nophead/NopSCADlib/releases/tag/v15.13.3 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.13.2...v15.13.3 "diff with v15.13.2")
+*   2021-05-19 [`0dab0dc`](https://github.com/nophead/NopSCADlib/commit/0dab0dca08485d1717ee516a61831fcd6963e335 "show commit") [C.P.](# "Chris Palmer") Added missing includes `core.scad` which generates warnings with latest OpenSCAD snapshots.
+
+ * Note, however, NopSCADlib does not work with the current OpenSCAD snapshot.
+
+#### [v15.13.2](https://github.com/nophead/NopSCADlib/releases/tag/v15.13.2 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.13.1...v15.13.2 "diff with v15.13.1")
+*   2021-05-15 [`9689683`](https://github.com/nophead/NopSCADlib/commit/9689683b7efbde882c057a903dd7fa018107d029 "show commit") [M.B.](# "Martin Budden") Typo in `global_defs`.
+
+#### [v15.13.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.13.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.13.0...v15.13.1 "diff with v15.13.0")
+*   2021-05-18 [`11ebe22`](https://github.com/nophead/NopSCADlib/commit/11ebe2225db09bdd45089e4ebf5c1037243bf45c "show commit") [C.P.](# "Chris Palmer") Removed spurious convexity in difference from `rounded_polygon()`.
+
+### [v15.13.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.13.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.12.0...v15.13.0 "diff with v15.12.0")
+*   2021-05-02 [`3401919`](https://github.com/nophead/NopSCADlib/commit/34019196cdac6b08e57d773e138a22394b609ea5 "show commit") [C.P.](# "Chris Palmer") Updated readme
+
+*   2021-05-02 [`436fc71`](https://github.com/nophead/NopSCADlib/commit/436fc71cf319c1e71b6cbd240b76d7cad5ecd8ba "show commit") [M.B.](# "Martin Budden") Added `blower_size` function.
+
+### [v15.12.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.12.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.11.1...v15.12.0 "diff with v15.11.1")
+*   2021-04-26 [`e2feceb`](https://github.com/nophead/NopSCADlib/commit/e2feceb608b4491424c0e4c1e7c191f7d8aeceec "show commit") [C.P.](# "Chris Palmer") Updated readme
+
+*   2021-04-25 [`9c1a9bf`](https://github.com/nophead/NopSCADlib/commit/9c1a9bf3572c07a57b5bd1fde1d9a4aba14e5ea8 "show commit") [M.B.](# "Martin Budden") Add facility to orient `core_xy` with left motor being lower or upper motor.
+
+#### [v15.11.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.11.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.11.0...v15.11.1 "diff with v15.11.0")
+*   2021-04-25 [`feec1e7`](https://github.com/nophead/NopSCADlib/commit/feec1e7ae5a5217586e0ab9e7b002e8af8f7c749 "show commit") [C.P.](# "Chris Palmer") Updated readme.
+
+*   2021-04-25 [`be76af2`](https://github.com/nophead/NopSCADlib/commit/be76af2fc490e10e4dd115a56019e33005f87db9 "show commit") [M.B.](# "Martin Budden") Fixed typo in `leadnut.scad`.
+
+### [v15.11.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.11.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.10.1...v15.11.0 "diff with v15.10.1")
+*   2021-04-25 [`49fdfea`](https://github.com/nophead/NopSCADlib/commit/49fdfea7926d677b6e0a9eee2fbd928f2935e1eb "show commit") [C.P.](# "Chris Palmer") Added 35BYGHJ75 geared stepper.
+
+#### [v15.10.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.10.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.10.0...v15.10.1 "diff with v15.10.0")
+*   2021-04-25 [`ac0bacf`](https://github.com/nophead/NopSCADlib/commit/ac0bacfeda43af62256e7bd3184df695b3e01d37 "show commit") [C.P.](# "Chris Palmer") Removed echo in rails test.
+
+### [v15.10.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.10.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.9.0...v15.10.0 "diff with v15.9.0")
+*   2021-04-13 [`e379fa8`](https://github.com/nophead/NopSCADlib/commit/e379fa8ada4a4089fc24ce5fc2c140a2531e2e95 "show commit") [C.P.](# "Chris Palmer") Updated readme.
+
+*   2021-04-13 [`5fbff06`](https://github.com/nophead/NopSCADlib/commit/5fbff060b019a983eba93eb8c5b16adfb6a3f7ee "show commit") [M.B.](# "Martin Budden") Added a `pcb_component` function.
+
+### [v15.9.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.9.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.8.0...v15.9.0 "diff with v15.8.0")
+*   2021-04-13 [`edc0b86`](https://github.com/nophead/NopSCADlib/commit/edc0b86bb1cd52e90fe353c4aea9539e95aa5aee "show commit") [C.P.](# "Chris Palmer") Updated images and readme.
+
+*   2021-03-31 [`b70c2f9`](https://github.com/nophead/NopSCADlib/commit/b70c2f993c351bf71da57cfc169ed02a235cf4f3 "show commit") [M.B.](# "Martin Budden") Added box sections.
+
+### [v15.8.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.8.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.7.0...v15.8.0 "diff with v15.7.0")
+*   2021-04-12 [`145c5d9`](https://github.com/nophead/NopSCADlib/commit/145c5d9b1a7c873940abf266a321edabdff3b7a0 "show commit") [C.P.](# "Chris Palmer") Updated readme.
+
+*   2021-04-12 [`1efed64`](https://github.com/nophead/NopSCADlib/commit/1efed649cf54607b9d39d4b7f422dd385ccb441f "show commit") [M.B.](# "Martin Budden") Added PSU size function.
+
+### [v15.7.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.7.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.6.1...v15.7.0 "diff with v15.6.1")
+*   2021-04-12 [`3f31607`](https://github.com/nophead/NopSCADlib/commit/3f31607840d162f63d12eb2317d2f28af1ecf492 "show commit") [C.P.](# "Chris Palmer") Added No8 screws.
+
+#### [v15.6.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.6.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.6.0...v15.6.1 "diff with v15.6.0")
+*   2021-04-05 [`f12b36e`](https://github.com/nophead/NopSCADlib/commit/f12b36ea046b5a784dd81b3c4e95eaf4cf24a58d "show commit") [C.P.](# "Chris Palmer") Corrected MGN12 rail end value.
+Added assert for rail end value too big.
+
+### [v15.6.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.6.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.5.0...v15.6.0 "diff with v15.5.0")
+*   2021-04-03 [`51cc2fd`](https://github.com/nophead/NopSCADlib/commit/51cc2fd6791065e1c94c761abf7dac0271e6ab28 "show commit") [C.P.](# "Chris Palmer") Carriages now appear on the BOM and both variants are shown in the rail test.
+
+*   2021-03-31 [`608168d`](https://github.com/nophead/NopSCADlib/commit/608168de8e56bfdde5ba605d27baca1900895926 "show commit") [M.B.](# "Martin Budden") Added MGN7H and MGN9H carriages.
+
+### [v15.5.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.5.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.4.0...v15.5.0 "diff with v15.4.0")
+*   2021-04-02 [`cc794cd`](https://github.com/nophead/NopSCADlib/commit/cc794cd7c3cd3e3f63d15ebbe5dabb773812ae72 "show commit") [C.P.](# "Chris Palmer") Updated readme.
+
+*   2021-03-31 [`fc45a40`](https://github.com/nophead/NopSCADlib/commit/fc45a40bd3c3b524d9edc226952482296e776831 "show commit") [M.B.](# "Martin Budden") Added translated children to pulley.
+
+### [v15.4.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.4.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.3.1...v15.4.0 "diff with v15.3.1")
+*   2021-04-02 [`b2d712b`](https://github.com/nophead/NopSCADlib/commit/b2d712bca94165a338e5f904880d12f9c4c5ecd0 "show commit") [C.P.](# "Chris Palmer") Added `quadratic_real_roots()` and `cubic_real_roots()`.
+
+#### [v15.3.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.3.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.3.0...v15.3.1 "diff with v15.3.0")
+*   2021-04-02 [`f3376ed`](https://github.com/nophead/NopSCADlib/commit/f3376edaf186b32f442b94d6d0b42f1ba0c7612c "show commit") [C.P.](# "Chris Palmer") Documented `xor()` function.
+
+### [v15.3.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.3.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.2.0...v15.3.0 "diff with v15.2.0")
+*   2021-04-02 [`c073419`](https://github.com/nophead/NopSCADlib/commit/c073419c0b4eddcda4cda5bd0f8d48268b6e58ec "show commit") [C.P.](# "Chris Palmer") Added `opengrab_screw_depth()` function.
+
+### [v15.2.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.2.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.1.1...v15.2.0 "diff with v15.1.1")
+*   2021-03-22 [`ca1b34e`](https://github.com/nophead/NopSCADlib/commit/ca1b34e9cad5d82bd878fa4ebf439c0fbdad7f77 "show commit") [C.P.](# "Chris Palmer") Added `sink` parameter to `screw_polysink()` to recess the head.
+
+#### [v15.1.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.1.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.1.0...v15.1.1 "diff with v15.1.0")
+*   2021-03-22 [`cbab9ce`](https://github.com/nophead/NopSCADlib/commit/cbab9cea028a204032a91729597572a39ed893a2 "show commit") [C.P.](# "Chris Palmer") Fixed `M6_cs_cap_screw`.
+
+### [v15.1.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.1.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v15.0.1...v15.1.0 "diff with v15.0.1")
+*   2021-03-21 [`4aa7dbb`](https://github.com/nophead/NopSCADlib/commit/4aa7dbb416773e42b2b5f77b345f18fcd4d2ae2c "show commit") [C.P.](# "Chris Palmer") Added `M6_cs_cap_screw`.
+
+#### [v15.0.1](https://github.com/nophead/NopSCADlib/releases/tag/v15.0.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v15.0.0...v15.0.1 "diff with v15.0.0")
+*   2021-03-21 [`7c7c2e5`](https://github.com/nophead/NopSCADlib/commit/7c7c2e5d3f76e84ae86892f9d90f21619fa61a47 "show commit") [C.P.](# "Chris Palmer") Pixel changes due to switch to summer computer.
+
+*   2021-03-15 [`f6f6664`](https://github.com/nophead/NopSCADlib/commit/f6f6664c0d06a7cc3d49f805a2fd4f4978a3a35a "show commit") [C.P.](# "Chris Palmer") Updated OpenSCAD version required.
+
+## [v15.0.0](https://github.com/nophead/NopSCADlib/releases/tag/v15.0.0 "show release") Breaking Changes [...](https://github.com/nophead/NopSCADlib/compare/v14.1.1...v15.0.0 "diff with v14.1.1")
+*   2021-03-14 [`9ded315`](https://github.com/nophead/NopSCADlib/commit/9ded3158010b577088fdaca8a25e478f48a27376 "show commit") [C.P.](# "Chris Palmer") Removed the belt gap options and changed the tests to use open loops instead.
+Note previous belt lengths were incorrect with negative turns.
+Fixed spelling typos.
+`_belt_length()` no longer needs belt type.
+Uptated images and readme.
+
+*   2021-03-14 [`d2c795f`](https://github.com/nophead/NopSCADlib/commit/d2c795f5f5c564ec4686a7857bd894738a93a6a0 "show commit") [S.](# "SmoothieAq") fix nan angle (hopefully)
+
+*   2021-03-14 [`573c507`](https://github.com/nophead/NopSCADlib/commit/573c50774bfb2edae25a415ca864abb39c4c1bcf "show commit") [S.](# "SmoothieAq") changes after review
+
+*   2021-03-11 [`2403347`](https://github.com/nophead/NopSCADlib/commit/240334784db8002468fe0f51c1f6404a64fe44a4 "show commit") [S.](# "SmoothieAq") Extension to `belt.scad`
+
+ * Can now:
+- render open loops
+- twist the belt
+- use pulleys instead of radius in the points list
+
+ * Fixes some precision a few places
+Breaking change in `belt_length();` now requires a type argument
+
+#### [v14.1.1](https://github.com/nophead/NopSCADlib/releases/tag/v14.1.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v14.1.0...v14.1.1 "diff with v14.1.0")
+*   2021-03-13 [`4b93623`](https://github.com/nophead/NopSCADlib/commit/4b93623492a2b8a073ab9dccc91fb2b21c475f21 "show commit") [C.P.](# "Chris Palmer") `changelog.py` now omits "Updated changelog" commits.
+
+### [v14.1.0](https://github.com/nophead/NopSCADlib/releases/tag/v14.1.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v14.0.1...v14.1.0 "diff with v14.0.1")
+*   2021-03-13 [`544e69c`](https://github.com/nophead/NopSCADlib/commit/544e69c71b404636df320be278b3fa7442f10429 "show commit") [C.P.](# "Chris Palmer") `pulley_pr()` now has an optional belt type for non-standard belt over smooth pulleys.
+
+#### [v14.0.1](https://github.com/nophead/NopSCADlib/releases/tag/v14.0.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v14.0.0...v14.0.1 "diff with v14.0.0")
+*   2021-03-08 [`e46e6b6`](https://github.com/nophead/NopSCADlib/commit/e46e6b6e5b95792b5b2b4d7a7e4360beed22df0b "show commit") [C.P.](# "Chris Palmer") Fixed markdown numbered points in `core_xy`.
+
 ## [v14.0.0](https://github.com/nophead/NopSCADlib/releases/tag/v14.0.0 "show release") Breaking Changes [...](https://github.com/nophead/NopSCADlib/compare/v13.5.0...v14.0.0 "diff with v13.5.0")
 *   2021-03-06 [`298d1f9`](https://github.com/nophead/NopSCADlib/commit/298d1f92841f30e13b437c6770fc113954b94108 "show commit") [C.P.](# "Chris Palmer") Interface is the same but filenames to be included or used changed.
-Changlog upated.
+Changelog updated.
 
 *   2021-03-06 [`491c3b4`](https://github.com/nophead/NopSCADlib/commit/491c3b4ea8d2ef51e55fd389f0dc0b9a6b9bd9a4 "show commit") [C.P.](# "Chris Palmer") Updated readme, `lib.scad` and image.
 
@@ -41,9 +276,7 @@ Changlog upated.
 
 *   2021-03-03 [`614e5f3`](https://github.com/nophead/NopSCADlib/commit/614e5f3a72db309a3dee996d7241317556883e8d "show commit") [C.P.](# "Chris Palmer") Issues in the changelog now link to to the issue.
 
-*   2021-03-03 [`a7eae4f`](https://github.com/nophead/NopSCADlib/commit/a7eae4f549b51dbe4624a8b67012919cef6cb24a "show commit") [C.P.](# "Chris Palmer") Neater changlog format.
-
-*   2021-03-03 [`7b770ab`](https://github.com/nophead/NopSCADlib/commit/7b770abe12b71fa4b4f7415aa9f46d0f2c9d54f1 "show commit") [C.P.](# "Chris Palmer") Udpated changelog
+*   2021-03-03 [`a7eae4f`](https://github.com/nophead/NopSCADlib/commit/a7eae4f549b51dbe4624a8b67012919cef6cb24a "show commit") [C.P.](# "Chris Palmer") Neater changelog format.
 
 *   2021-03-03 [`31ab856`](https://github.com/nophead/NopSCADlib/commit/31ab8562a783464f93812b8c7c45d403587efd0a "show commit") [C.P.](# "Chris Palmer") Updated images
 
@@ -66,7 +299,7 @@ Changlog upated.
 *   2021-02-20 [`03a0c2f`](https://github.com/nophead/NopSCADlib/commit/03a0c2fe981ce12cda51a693f69b4fb19696cb8a "show commit") [C.P.](# "Chris Palmer") Fixed typo.
 
 ### [v13.3.0](https://github.com/nophead/NopSCADlib/releases/tag/v13.3.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v13.2.0...v13.3.0 "diff with v13.2.0")
-*   2021-02-20 [`7c2df8d`](https://github.com/nophead/NopSCADlib/commit/7c2df8d36d214a8bf8ebdcd39da293209bc175ab "show commit") [C.P.](# "Chris Palmer") The pose module can now specify the camera distance supressing viewall and
+*   2021-02-20 [`7c2df8d`](https://github.com/nophead/NopSCADlib/commit/7c2df8d36d214a8bf8ebdcd39da293209bc175ab "show commit") [C.P.](# "Chris Palmer") The pose module can now specify the camera distance suppressing viewall and
 autocentre.
 
 ### [v13.2.0](https://github.com/nophead/NopSCADlib/releases/tag/v13.2.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v13.1.0...v13.2.0 "diff with v13.1.0")
@@ -361,9 +594,9 @@ Updated pics and readme.
 *   2020-12-28 [`ba586b3`](https://github.com/nophead/NopSCADlib/commit/ba586b368582db163af143ebb60afed270f77b1c "show commit") [C.P.](# "Chris Palmer") Example images update to match new contersink screws and teardrops.
 
 ### [v10.21.0](https://github.com/nophead/NopSCADlib/releases/tag/v10.21.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v10.20.1...v10.21.0 "diff with v10.20.1")
-*   2020-12-28 [`8d22940`](https://github.com/nophead/NopSCADlib/commit/8d22940506df525ac52ef6f8a00ea03661f3b682 "show commit") [C.P.](# "Chris Palmer") Project blurb can now be split with into sections with markdown horizonal rules
+*   2020-12-28 [`8d22940`](https://github.com/nophead/NopSCADlib/commit/8d22940506df525ac52ef6f8a00ea03661f3b682 "show commit") [C.P.](# "Chris Palmer") Project blurb can now be split with into sections with markdown horizontal rules
 made with asterisks.
-If an image is include in the first section the default image is supressed.
+If an image is include in the first section the default image is suppressed.
 
 #### [v10.20.1](https://github.com/nophead/NopSCADlib/releases/tag/v10.20.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v10.20.0...v10.20.1 "diff with v10.20.0")
 *   2020-12-26 [`87c8bbb`](https://github.com/nophead/NopSCADlib/commit/87c8bbb9a549aabb84004426332dc964583472c5 "show commit") [M.B.](# "Martin Budden") Fixed error in `carriage_size` function.
@@ -378,12 +611,12 @@ If an image is include in the first section the default image is supressed.
 
 ### [v10.20.0](https://github.com/nophead/NopSCADlib/releases/tag/v10.20.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v10.19.0...v10.20.0 "diff with v10.19.0")
 *   2020-12-24 [`6f8ff60`](https://github.com/nophead/NopSCADlib/commit/6f8ff606fa5b2ef7d81fb687b77bd6236f6d277f "show commit") [C.P.](# "Chris Palmer") Removed `woven_sheet()` from the readme.
-Removed redundent code.
+Removed redundant code.
 
 *   2020-12-24 [`acd5de0`](https://github.com/nophead/NopSCADlib/commit/acd5de0fbd513b67387478b4c89a5ef4f11b440b "show commit") [C.P.](# "Chris Palmer") Fixed extra BOM entries for woven sheet.
 Added render colour to BOM for 3D sheets.
 
-*   2020-12-23 [`cc1e3ba`](https://github.com/nophead/NopSCADlib/commit/cc1e3baaf6ba7451b3545efc949015af822dc95c "show commit") [C.P.](# "Chris Palmer") Reimplemeted woven sheets with an eye to speed and interface consistancy.
+*   2020-12-23 [`cc1e3ba`](https://github.com/nophead/NopSCADlib/commit/cc1e3baaf6ba7451b3545efc949015af822dc95c "show commit") [C.P.](# "Chris Palmer") Reimplemeted woven sheets with an eye to speed and interface consistency.
 
 *   2020-12-13 [`85cb54e`](https://github.com/nophead/NopSCADlib/commit/85cb54ef318597a4922077785247ddcb08d5e00d "show commit") [M.B.](# "Martin Budden") Added sheet with checkerboard texture to simulate carbon fiber.
 
@@ -848,7 +1081,7 @@ Done to reduced the number of global constants.
 `Panel_meters` can now have inner apertures and buttons.
 
 ### [v7.2.0](https://github.com/nophead/NopSCADlib/releases/tag/v7.2.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v7.1.1...v7.2.0 "diff with v7.1.1")
-*   2020-05-02 [`baa737c`](https://github.com/nophead/NopSCADlib/commit/baa737c4d83be0ab38685122ebe535872fe63e20 "show commit") [C.P.](# "Chris Palmer") Updated example to use Foot contructor.
+*   2020-05-02 [`baa737c`](https://github.com/nophead/NopSCADlib/commit/baa737c4d83be0ab38685122ebe535872fe63e20 "show commit") [C.P.](# "Chris Palmer") Updated example to use Foot constructor.
 
 *   2020-05-02 [`70b13d2`](https://github.com/nophead/NopSCADlib/commit/70b13d2f2723caa18a69afb7a179d88366c82c51 "show commit") [C.P.](# "Chris Palmer") Added functions to create property lists that are created by the client.
 Foot, box, bbox, pbox, `flat_hinge` and `strap_handle`.
@@ -1052,7 +1285,7 @@ The implementation files are still lower case for backwards compatibility.
 
 *   2020-03-03 [`bd60b50`](https://github.com/nophead/NopSCADlib/commit/bd60b50b099d76f6588ddfe900be276ed7d0cf98 "show commit") [C.P.](# "Chris Palmer") Removed lower case tests
 
-*   2020-03-03 [`4d51cb7`](https://github.com/nophead/NopSCADlib/commit/4d51cb73f3d2b3a92ac4c12a2002bc4918228969 "show commit") [C.P.](# "Chris Palmer") Table of contents now has three vitamin coloumns
+*   2020-03-03 [`4d51cb7`](https://github.com/nophead/NopSCADlib/commit/4d51cb73f3d2b3a92ac4c12a2002bc4918228969 "show commit") [C.P.](# "Chris Palmer") Table of contents now has three vitamin columns
 
 *   2020-03-02 [`3b77c97`](https://github.com/nophead/NopSCADlib/commit/3b77c975325851caf5e602ae6ceaa8e5d9126425 "show commit") [C.P.](# "Chris Palmer") Example now include `core.scad` instead of `lib.scad`.
 
@@ -1329,7 +1562,7 @@ This means 5mm, 6mm etc comes before 10mm in BOM.
 
 *   2020-01-11 [`d1324a6`](https://github.com/nophead/NopSCADlib/commit/d1324a670eb7ec898e6663dc9394fc1bd19ef664 "show commit") [M.B.](# "Martin Budden") Added JST-XH connector for pcbs.
 
-*   2020-02-22 [`599fbba`](https://github.com/nophead/NopSCADlib/commit/599fbba6c2b036a4a22fa04f2e06f67ef5bb9578 "show commit") [C.P.](# "Chris Palmer") Reduced dependecies in `pcb_mount` test.
+*   2020-02-22 [`599fbba`](https://github.com/nophead/NopSCADlib/commit/599fbba6c2b036a4a22fa04f2e06f67ef5bb9578 "show commit") [C.P.](# "Chris Palmer") Reduced dependencies in `pcb_mount` test.
 
 ### [v2.19.0](https://github.com/nophead/NopSCADlib/releases/tag/v2.19.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v2.16.0...v2.19.0 "diff with v2.16.0")
 *   2020-02-22 [`6097e07`](https://github.com/nophead/NopSCADlib/commit/6097e0709498166c61712094fcc11f083e25959f "show commit") [C.P.](# "Chris Palmer") Updated images and readme.
@@ -1645,7 +1878,7 @@ IEC screw length fixed at 10 if inserts used.
 *   2019-06-14 [`a51e96e`](https://github.com/nophead/NopSCADlib/commit/a51e96ec433c6d347e0d313573585cda9978e7b4 "show commit") [C.P.](# "Chris Palmer") Nuts now show their thickness on the BOM so half nuts have a different description.
 
 ## [v1.0.0](https://github.com/nophead/NopSCADlib/releases/tag/v1.0.0 "show release") Breaking Changes [...](https://github.com/nophead/NopSCADlib/compare/v0.0.1...v1.0.0 "diff with v0.0.1")
-*   2019-06-14 [`b719601`](https://github.com/nophead/NopSCADlib/commit/b719601a645d899f5477c13a34f857d178bcc3a1 "show commit") [C.P.](# "Chris Palmer") Fixed cable strip parameters and BOM desciption
+*   2019-06-14 [`b719601`](https://github.com/nophead/NopSCADlib/commit/b719601a645d899f5477c13a34f857d178bcc3a1 "show commit") [C.P.](# "Chris Palmer") Fixed cable strip parameters and BOM description
 
 #### [v0.0.1](https://github.com/nophead/NopSCADlib/releases/tag/v0.0.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v0.0.0...v0.0.1 "diff with v0.0.0")
 *   2019-06-14 [`5ede2d0`](https://github.com/nophead/NopSCADlib/commit/5ede2d0895a8a813ef2bc47bf94462d668bc440b "show commit") [C.P.](# "Chris Palmer") Smooth pulleys now show their OD on the BOM.

docs/usage.md

@@ -1,7 +1,7 @@
 # NopSCADlib usage
 
 ## Requirements
-1. OpenSCAD 2019.05 or later, download it from here: https://www.openscad.org/downloads.html
+1. OpenSCAD 2021.01 or later, download it from here: https://www.openscad.org/downloads.html
 1. Python 2.7+ or 3.6+ from https://www.python.org/downloads/
 1. ImageMagick 7 www.imagemagick.org
 
@@ -270,6 +270,22 @@ The target config file is selected by generating `target.scad` that includes `co
 The rest of the project includes `target.scad` to use the configuration.
 Additionally all the generated file directories (assemblies, bom, stls, dxfs, etc.) are placed in a sub-directory called `<target_name>`.
 
+The build system will look for a `<target_name>_assembly` module and use it as the top level module instead of `main_assembly` if it it exists.
+That allows the project description to be target specific if the top level modules are in different scad files.
+The top level assembly instructions and assembly contents could also be different if appropriate.
+
+If the top level module is just a shell wrapper that simply includes one other assembly, with no additional parts, then it is removed from the build instructions and
+the assembly it calls becomes the top level. This allows a different project description for each target but only one set of top level instructions without repeating them.
+
+### Costed BOMs
+
+A costed bill of materials can be made by opening the generated file `bom/bom.csv` in a spreadsheet program using a single quote as the string delimiter and comma as the field separator.
+That gets a list of part descriptions and quantities to which prices can be added to get the total cost and perhaps a URL of where to buy each part.
+
+If a Python file called `parts.py` is found then `bom.py` will attempt to call functions for each part to get a price and URL.
+Any functions not found are printed, so you can see the format expected.
+The function are passed the quantity to allow them to calculate volume discounts, etc.
+
 ### Other libraries
 
 The build scripts need to be able to locate the source files where the modules to generate the STL files and assemblies reside. They will search all the scad files

examples/MainsBreakOutBox/bom/bom.csv

@@ -0,0 +1,16 @@
+'Ferrule for 1.5mm^2 wire - not shown',  3
+'Wire blue 30/0.25mm strands, length 150mm - not shown',  2
+'Wire brown 30/0.25mm strands, length 150mm - not shown',  2
+'Wire green & yellow 30/0.25mm strands, length 150mm - not shown',  2
+'IEC inlet for ATX',  1
+'Heatfit insert M3',  2
+'4mm shielded jack socket blue',  2
+'4mm shielded jack socket brown',  1
+'4mm shielded jack socket green',  2
+'Mains socket 13A',  1
+'Nut M3 x 2.4mm nyloc',  6
+'Screw M3 cs cap x 12mm',  2
+'Screw M3 cs cap x 20mm',  2
+'Screw M3 dome x 10mm',  4
+'Heatshrink sleeving ID 3.2mm x 15mm - not shown',  8
+'Washer  M3 x 7mm x 0.5mm', 10

global_defs.scad

@@ -27,15 +27,16 @@
 //  Setting $_bom in the local file overrides it in the local file but not in the libs.
 //
 rr_green = [0, 146/255, 0];                                               // RepRap logo colour
+crimson  = [220/255, 20/255, 60/255];
 
 $_bom           = is_undef($bom)             ? 0      : $bom;             // 0 no bom, 1 assemblies and stls, 2 vitamins as well
 $exploded       = is_undef($explode)         ? 0      : $explode;         // 1 for exploded view
-layer_height    = is_undef($layer_height)    ? 0.25   : $layer_height;    // layer heigth when printing
+layer_height    = is_undef($layer_height)    ? 0.25   : $layer_height;    // layer height when printing
 extrusion_width = is_undef($extrusion_width) ? 0.5    : $extrusion_width; // filament width when printing
 nozzle          = is_undef($nozzle)          ? 0.45   : $nozzle;          // 3D printer nozzle
 cnc_bit_r       = is_undef($cnc_bit_r)       ? 1.2    : $cnc_bit_r;       // minimum tool radius when milling 2D objects
 pp1_colour      = is_undef($pp1_colour)      ? rr_green : $pp1_colour;    // printed part colour 1, RepRap logo colour
-pp2_colour      = is_undef($pp2_colour)      ? "Crimson"  : $pp2_colour;  // printed part colour 2
+pp2_colour      = is_undef($pp2_colour)      ? crimson : $pp2_colour;     // printed part colour 2
 pp3_colour      = is_undef($pp3_colour)      ? "SteelBlue" : $pp3_colour; // printed part colour 3
 pp4_colour      = is_undef($pp4_colour)      ? "darkorange" : $pp4_colour;// printed part colour 4
 show_rays       = is_undef($show_rays)       ? false  : $show_rays;       // show camera sight lines and light direction
@@ -53,9 +54,10 @@ $fs = extrusion_width / 2;
 function round_to_layer(z) = ceil(z / layer_height) * layer_height;
 // Some additional named colours
 function grey(n) = [0.01, 0.01, 0.01] * n;                                          //! Generate a shade of grey to pass to color().
-gold                            = [255/255, 215/255, 0/255];
-brass                           = [255/255, 220/255, 100/255];
 silver                          = [0.75, 0.75, 0.75];
+gold                            = [255, 215,   0] / 255;
+brass                           = [255, 220, 100] / 255;
+copper                          = [230, 140,  51] / 255;
 
 /*
  * Enums

lib.scad

@@ -28,6 +28,8 @@ include <vitamins/pcbs.scad>
 include <vitamins/batteries.scad>
 include <vitamins/bearing_blocks.scad>
 include <vitamins/blowers.scad>
+include <vitamins/bldc_motors.scad>
+include <vitamins/box_sections.scad>
 include <vitamins/bulldogs.scad>
 include <vitamins/buttons.scad>
 include <vitamins/cameras.scad>
@@ -53,6 +55,7 @@ include <vitamins/pulleys.scad>
 include <vitamins/ring_terminals.scad>
 include <vitamins/rails.scad>
 include <vitamins/rod.scad>
+include <vitamins/servo_motors.scad>
 include <vitamins/shaft_couplings.scad>
 include <vitamins/sheets.scad>
 include <vitamins/sk_brackets.scad>

libtest.scad

@@ -45,7 +45,9 @@ use <tests/ball_bearings.scad>
 use <tests/batteries.scad>
 use <tests/bearing_blocks.scad>
 use <tests/belts.scad>
+use <tests/BLDC_motors.scad>
 use <tests/blowers.scad>
+use <tests/box_sections.scad>
 use <tests/bulldogs.scad>
 use <tests/buttons.scad>
 use <tests/cable_strips.scad>
@@ -90,6 +92,7 @@ use <tests/rockers.scad>
 use <tests/rod.scad>
 use <tests/screws.scad>
 use <tests/sealing_strip.scad>
+use <tests/servo_motors.scad>
 use <tests/shaft_couplings.scad>
 use <tests/sheets.scad>
 use <tests/SK_brackets.scad>
@@ -183,16 +186,15 @@ translate([x5, cable_grommets_y + 250])
 translate([950, 600])
     box_test();
 
-translate([830, 770])
+translate([900, 750])
     pocket_handles();
 
-translate([950, 750])
+translate([900, 850])
     printed_boxes();
 
-translate([850, 1330])
+translate([850, 1330 + 85])
     bbox_test();
 
-
 inserts_y = 0;
 nuts_y = inserts_y + 20;
 washers_y = nuts_y + 120;
@@ -204,10 +206,11 @@ sealing_strip_y = springs_y + 20;
 tubings_y = sealing_strip_y + 20;
 pillars_y = tubings_y + 20;
 ball_bearings_y = pillars_y + 40;
-pulleys_y = ball_bearings_y +40;
-hot_ends_y = pulleys_y + 60;
-linear_bearings_y = hot_ends_y + 50;
-sheets_y = linear_bearings_y + 90;
+pulleys_y = ball_bearings_y + 40;
+leadnuts_y = pulleys_y + 60;
+linear_bearings_y = leadnuts_y + 50;
+steppers_y = linear_bearings_y + 110;
+sheets_y = steppers_y + 55;
 pcbs_y = sheets_y + 60;
 displays_y = pcbs_y + 170;
 fans_y = displays_y + 80;
@@ -253,13 +256,16 @@ translate([x0, ball_bearings_y])
 translate([x0, pulleys_y])
     pulleys();
 
+translate([x0, leadnuts_y])
+    leadnuts();
+
 translate([x0, linear_bearings_y]) {
     linear_bearings();
     rods();
 }
 
-translate([x0 + 10, hot_ends_y])
-    hot_ends();
+translate([x0, steppers_y])
+    stepper_motors();
 
 translate([x0, sheets_y])
     sheets();
@@ -277,7 +283,7 @@ translate([x0, fans_y]) {
         fan_guards();
 }
 
-translate([x0, transformers_y])
+translate([760, fans_y])
     variacs();
 
 translate([x0, psus_y]) {
@@ -289,7 +295,6 @@ translate([x0, psus_y]) {
 zipties_y = 0;
 bulldogs_y = zipties_y + 30;
 swiss_clips_y = bulldogs_y + 35;
-leadnuts_y = swiss_clips_y + 50;
 
 translate([x1, zipties_y])
     zipties();
@@ -300,10 +305,6 @@ translate([x1, bulldogs_y])
 translate([x1, swiss_clips_y])
     swiss_clips();
 
-translate([x1, leadnuts_y])
-    leadnuts();
-
-
 leds_y = 0;
 carriers_y = leds_y + 40;
 magnets_y = carriers_y + 40;
@@ -360,18 +361,18 @@ iecs_y = d_connectors_y + 80;
 modules_y = iecs_y + 60;
 ssrs_y = modules_y + 80;
 blowers_y = ssrs_y + 60;
-batteries_y = blowers_y + 100;
-steppers_y = batteries_y + 55;
-panel_meters_y = steppers_y + 70;
+hot_ends_y = blowers_y + 100;
+batteries_y = hot_ends_y + 55;
+panel_meters_y = batteries_y + 70;
 extrusions_y = panel_meters_y + 80;
 
 translate([x3, veroboard_y])
     veroboard_test();
 
-translate([x3 + 70, veroboard_y + 30])
+translate([x3 + 60, veroboard_y + 20])
     geared_steppers();
 
-translate([x3 + 140, veroboard_y + 20])
+translate([x3 + 160, ssrs_y])
     pcb_mounts();
 
 translate([x3 + 170, veroboard_y + 16])
@@ -407,8 +408,8 @@ translate([x3, blowers_y])
 translate([x3, batteries_y])
     batteries();
 
-translate([x2, steppers_y])  // interloper
-    stepper_motors();
+translate([x3 + 10, hot_ends_y])
+    hot_ends();
 
 translate([x2, panel_meters_y])
     panel_meters();
@@ -416,7 +417,7 @@ translate([x2, panel_meters_y])
 translate([x2, extrusions_y])
     extrusions();
 
-translate([x3, transformers_y])
+translate([400, transformers_y])
     transformers();
 
 
@@ -424,15 +425,20 @@ belts_y = 0;
 rails_y = belts_y + 200;
 extrusion_brackets_y = rails_y + 250;
 sk_brackets_y = extrusion_brackets_y + 80;
-kp_pillow_blocks_y = sk_brackets_y + 50;
+kp_pillow_blocks_y = sk_brackets_y + 60;
 scs_bearing_blocks_y = kp_pillow_blocks_y + 60;
+cable_strip_y = sheets_y;
+box_sections_y = batteries_y;
+BLDC_y = steppers_y;
+
+translate([0, transformers_y])
+    servo_motors();
 
 translate([x4 + 200, belts_y + 58]) {
     belt_test();
 
     translate([0, 60])
         opengrab_test();
-
 }
 
 translate([x4 + 175, belts_y, -20])
@@ -441,7 +447,7 @@ translate([x4 + 175, belts_y, -20])
 translate([x4, rails_y + 130])
     rails();
 
-translate([770, fans_y + 50])
+translate([x4, cable_strip_y])
     cable_strips();
 
 translate([x4, kp_pillow_blocks_y])
@@ -453,12 +459,17 @@ translate([x4, sk_brackets_y])
 translate([x4, extrusion_brackets_y])
     extrusion_brackets();
 
-translate([x4 + 120, extrusion_brackets_y])
+translate([x1, swiss_clips_y + 50])
     shaft_couplings();
 
 translate([x4, scs_bearing_blocks_y])
     scs_bearing_blocks();
 
+translate([x4, BLDC_y])
+    bldc_motors();
+
+translate([x2, box_sections_y])
+    box_sections();
 
 translate([x6, 125])
     light_strips();

printed/butt_box.scad

@@ -54,7 +54,7 @@ function bbox(screw, sheets, base_sheet, top_sheet, span, size, name = "bbox", s
  [ screw, sheets, base_sheet, top_sheet, span, size.x, size.y, size.z, name, skip_blocks, star_washers ];
 
 function bbox_volume(type) = bbox_width(type) * bbox_depth(type) * bbox_height(type) / 1000000; //! Internal volume in litres
-function bbox_area(type) = let(w =  bbox_width(type), d = bbox_depth(type), h = bbox_height(type)) //! Internal surdface area in m^2
+function bbox_area(type) = let(w =  bbox_width(type), d = bbox_depth(type), h = bbox_height(type)) //! Internal surface area in m^2
     2 * (w * d + w * h + d * h) / 1000000;
 
 module bbox_shelf_blank(type) { //! 2D template for a shelf

printed/door_hinge.scad

@@ -45,7 +45,7 @@ function door_hinge_stat_screw() = stat_screw;              //! Screw use to fas
 function door_hinge_stat_width() = stat_width;              //! Width of the stationary part
 function door_hinge_stat_length() = stat_length;            //! Length of the stationary part
 
-module door_hinge_hole_positions(dir = 0) {                 //! Position chidren at the door hole positions
+module door_hinge_hole_positions(dir = 0) {                 //! Position children at the door hole positions
     hole_pitch = width - 10;
 
     for(side = [-1, 1])

printed/door_latch.scad

@@ -57,7 +57,7 @@ module door_latch_stl() { //! Generates the STL for the printed part
         }
 }
 
-module door_latch_assembly(sheet_thickness = 3) { //! The assembly for a specified sheet thickess
+module door_latch_assembly(sheet_thickness = 3) { //! The assembly for a specified sheet thickness
     washer = screw_washer(screw);
     nut = screw_nut(screw);
 

printed/drag_chain.scad

@@ -20,7 +20,7 @@
 //
 //! Parametric cable drag chain to limit the bend radius of a cable run.
 //!
-//! Each link has a maximum bend angle of 45°, so the mininium radius is proportional to the link length.
+//! Each link has a maximum bend angle of 45°, so the minimum radius is proportional to the link length.
 //!
 //! The travel property is how far it can move in each direction, i.e. half the maximum travel if the chain is mounted in the middle of the travel.
 //!

printed/fan_guard.scad

@@ -17,7 +17,7 @@
 // If not, see <https://www.gnu.org/licenses/>.
 
 //
-//! Pintable fan finger guard to match the specified fan. To be `include`d, not `use`d.
+//! Printable fan finger guard to match the specified fan. To be `include`d, not `use`d.
 //!
 //! The ring spacing as well as the number of spokes can be specified, if zero a gasket is generated instead of a guard.
 //

printed/flat_hinge.scad

@@ -40,7 +40,7 @@ function hinge_knuckles(type)    = type[6]; //! How many knuckles
 function hinge_screw(type)       = type[7]; //! Screw type to mount it
 function hinge_screws(type)      = type[8]; //! How many screws
 function hinge_clearance(type)   = type[9]; //! Clearance between knuckles
-function hinge_margin(type)      = type[10]; //! How far to keep the screws from the knuckes
+function hinge_margin(type)      = type[10]; //! How far to keep the screws from the knuckles
 
 function flat_hinge(name, size, pin_d, knuckle_d, knuckles, screw, screws, clearance, margin) = //! Construct the property list for a flat hinge.
  [name, size.x, size.y, size.z, pin_d, knuckle_d, knuckles, screw, screws, clearance, margin];
@@ -73,7 +73,7 @@ module hinge_male(type, female = false) {       //! The half with the stationary
     assert(kr > pr, "knuckle diameter must be bigger than the pin diameter");
 
     n = hinge_knuckles(type);
-    assert(n >= 3, "must be at least three knuckes");
+    assert(n >= 3, "must be at least three knuckles");
     mn = ceil(n / 2);                           // Male knuckles
     fn = floor(n / 2);                          // Female knuckles
     gap = hinge_clearance(type);

printed/psu_shroud.scad

@@ -41,6 +41,7 @@ overlap = 6;
 cable_tie_inset = wall + 4;
 
 function psu_shroud_extent(type) = 15 + wall;                                   //! How far it extends beyond the PSU to clear the connections
+function psu_shroud_wall(type) = wall;                                          //! The wall thickness
 function psu_shroud_depth(type) =                                               //! Outside depth of the shroud
     psu_left_bay(type) + overlap + psu_shroud_extent(type);
 
@@ -154,7 +155,7 @@ assembly(str("PSU_shroud_", name), ngb = true) {
             insert(insert);
 }
 
-module psu_shroud_fastened_assembly(type, cable_d, thickness, name, cables = 1) //! Assembly with screws in place
+module psu_shroud_fastened_assembly(type, cable_d, thickness, name, cables = 1, screw = screw) //! Assembly with screws in place
 {
     screw_length = screw_length(screw,thickness + counter_bore, 2, true);
 

scripts/bom.py

@@ -31,6 +31,12 @@ from set_config import *
 import json
 import re
 
+try:
+    import parts
+    got_parts_py = True
+except:
+    got_parts_py = False
+
 def find_scad_file(mname):
     for filename in os.listdir(source_dir):
         if filename[-5:] == ".scad":
@@ -46,6 +52,18 @@ def find_scad_file(mname):
                             return filename
     return None
 
+def main_assembly(target):
+    file = None
+    if target:
+        assembly = target + "_assembly"
+        file = find_scad_file(assembly)
+    if not file:
+        assembly = "main_assembly"
+        file = find_scad_file(assembly)
+    if not file:
+        raise Exception("can't find source for " + assembly)
+    return assembly, file
+
 class Part:
     def __init__(self, args):
         self.count = 1
@@ -117,6 +135,33 @@ class BOM:
             return ass
         return ass.replace("assembly", "assemblies")
 
+    def print_CSV(self,  file = None):
+        i = 0
+        for part in sorted(self.vitamins):
+            i += 1
+            if ': ' in part:
+                part_no, description = part.split(': ')
+            else:
+                part_no, description = "", part
+            qty = self.vitamins[part].count
+            if got_parts_py:
+                match = re.match(r'^.*\((.*?)[,\)].*$', part_no)
+                if match and not match.group(1).startswith('"'):
+                    part_no = part_no.replace('(' + match.group(1), '_' + match.group(1) + '(').replace('(, ', '(')
+                func = 'parts.' + part_no.replace('(', '(%d, ' % qty).replace(', )', ')')
+                func = func.replace('true',  'True').replace('false', 'False').replace('undef', 'None')
+                try:
+                    price, url = eval(func)
+                    print("'%s',%3d,%.2f,'=B%d*C%d',%s" % (description, qty, price, i, i, url), file=file)
+                except:
+                    if part_no:
+                        print("%s not found in parts.py" % func)
+                    print("'%s',%3d" % (description, qty), file=file)
+            else:
+                print("'%s',%3d" % (description, qty), file=file)
+        if got_parts_py:
+            print(",'=SUM(B1:B%d)',,'=SUM(D1:D%d)'" %(i, i), file=file)
+
     def print_bom(self, breakdown, file = None):
         if self.vitamins:
             print("Vitamins:", file=file)
@@ -221,28 +266,20 @@ def parse_bom(file = "openscad.log", name = None):
     return main
 
 def usage():
-    print("\nusage:\n\tbom [target_config] [<accessory_name>_assembly] - Generate BOMs for a project or an accessory to a project.")
+    print("\nusage:\n\tbom [target_config] - Generate BOMs for a project.")
     sys.exit(1)
 
-def boms(target = None, assembly = None):
+def boms(target = None):
     try:
         bom_dir = set_config(target, usage) + "bom"
-        if assembly:
-            bom_dir += "/accessories"
-            if not os.path.isdir(bom_dir):
-                os.makedirs(bom_dir)
-        else:
-            assembly = "main_assembly"
-            if os.path.isdir(bom_dir):
-                shutil.rmtree(bom_dir)
-                sleep(0.1)
-            os.makedirs(bom_dir)
+        if os.path.isdir(bom_dir):
+            shutil.rmtree(bom_dir)
+            sleep(0.1)
+        os.makedirs(bom_dir)
         #
-        # Find the scad file that makes the module
+        # Find the scad file that makes the main assembly
         #
-        scad_file = find_scad_file(assembly)
-        if not scad_file:
-            raise Exception("can't find source for " + assembly)
+        assembly, scad_file = main_assembly(target)
         #
         # make a file to use the module
         #
@@ -259,8 +296,9 @@ def boms(target = None, assembly = None):
 
         main = parse_bom("openscad.echo", assembly)
 
-        if assembly == "main_assembly":
-            main.print_bom(True, open(bom_dir + "/bom.txt","wt"))
+        main.print_bom(True, open(bom_dir + "/bom.txt","wt"))
+
+        main.print_CSV(open(bom_dir + "/bom.csv","wt"))
 
         for ass in main.assemblies:
             with open(bom_dir + "/" + ass + ".txt", "wt") as f:
@@ -278,20 +316,8 @@ def boms(target = None, assembly = None):
         sys.exit(1)
 
 if __name__ == '__main__':
-    if len(sys.argv) > 3: usage()
+    if len(sys.argv) > 2: usage()
 
-    if len(sys.argv) == 3:
-        target, assembly = sys.argv[1], sys.argv[2]
-    else:
-        if len(sys.argv) == 2:
-            if sys.argv[1][-9:] == "_assembly":
-                target, assembly = None, sys.argv[1]
-            else:
-                target, assembly = sys.argv[1], None
-        else:
-            target, assembly = None, None
+    target = sys.argv[1] if len(sys.argv) == 2 else None
 
-    if assembly:
-        if assembly[-9:] != "_assembly": usage()
-
-    boms(target, assembly)
+    boms(target)

scripts/changelog.py

@@ -24,6 +24,7 @@ from __future__ import print_function
 import sys
 import subprocess
 import re
+from tests import do_cmd
 
 filename = 'CHANGELOG.md'
 
@@ -159,5 +160,7 @@ if __name__ == '__main__':
                 print('%s [%s](%s "show release") %s %s' % ('#' * (level + 1), ver, url + '/releases/tag/' + ver, type, diff), file = file)
 
             # Print commits excluding merges
-            if not c.comment.startswith('Merge branch') and not c.comment.startswith('Merge pull'):
+
+            if not c.comment.startswith('Merge branch') and not c.comment.startswith('Merge pull') and not re.match(r'U..ated changelog.*', c.comment):
                 print('* %s [`%s`](%s "show commit") %s %s\n' % (c.date, c.hash[:7], url + '/commit/' + c.hash, initials(c.author), fixup_comment(c.comment, url)), file = file)
+    do_cmd(('codespell -w -L od ' + filename).split())

scripts/options.py

@@ -17,7 +17,7 @@
 # If not, see <https://www.gnu.org/licenses/>.
 #
 
-# Set command line options from enviroment variables and check if they have changed
+# Set command line options from environment variables and check if they have changed
 
 import json, os, deps
 from colorama import Fore, init

scripts/tests.py

@@ -173,7 +173,7 @@ def tests(tests):
                     impl_name = None
 
             if libtest:
-                vsplit = "AJR" + chr(ord('Z') + 1)
+                vsplit = "AIR" + chr(ord('Z') + 1)
                 vtype = locations[0][1]
                 types = [vtype + ' ' + vsplit[i] + '-' + chr(ord(vsplit[i + 1]) - 1) for i in range(len(vsplit) - 1)] + [loc[1] for loc in locations[1 :]]
                 if type == vtype:

scripts/views.py

@@ -77,12 +77,12 @@ def bom_to_assemblies(bom_dir, bounds_map):
     #
     if flat_bom:
         ass = flat_bom[-1]
-        if len(ass["assemblies"]) < 2 and not ass["vitamins"] and not ass["printed"] and not ass["routed"]:
+        if len(ass["assemblies"]) == 1 and not ass["vitamins"] and not ass["printed"] and not ass["routed"]:
             flat_bom = flat_bom[:-1]
     return [assembly["name"] for  assembly in flat_bom]
 
 def eop(doc_file, last = False, first = False):
-    print('<span></span>', file = doc_file)     # An invisable marker for page breaks because markdown takes much longer if the document contains a div
+    print('<span></span>', file = doc_file)     # An invisible marker for page breaks because markdown takes much longer if the document contains a div
     if not first:
         print('[Top](#TOP)', file = doc_file)
     if not last:
@@ -161,6 +161,7 @@ def views(target, do_assemblies = None):
     # Find all the scad files
     #
     main_blurb = None
+    main_assembly, main_file = bom.main_assembly(target)
     pngs = []
     for dir in source_dirs(bom_dir):
         if os.path.isdir(dir):
@@ -232,7 +233,7 @@ def views(target, do_assemblies = None):
                                                 update_image(tmp_name, tn_name)
                                     done_assemblies.append(real_name)
                                 else:
-                                    if module == 'main_assembly':
+                                    if module == main_assembly:
                                         main_blurb = blurb.scrape_module_blurb(lines[:line_no])
                         line_no += 1
     #
@@ -246,9 +247,6 @@ def views(target, do_assemblies = None):
         project = ' '.join(word[0].upper() + word[1:] for word in os.path.basename(os.getcwd()).split('_'))
         print('<a name="TOP"></a>', file = doc_file)
         print('# %s' % project, file = doc_file)
-        main_file = bom.find_scad_file('main_assembly')
-        if not main_file:
-            raise Exception("can't find source for main_assembly")
         text = blurb.scrape_blurb(source_dir + '/' + main_file)
         blurbs = blurb.split_blurb(text)
         if len(text):

tests/BLDC_motors.scad

@@ -0,0 +1,31 @@
+//
+// NopSCADlib Copyright Chris Palmer 2021
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+include <../core.scad>
+use <../utils/layout.scad>
+
+include <../vitamins/bldc_motors.scad>
+
+module bldc_motors()
+    layout([for(b = bldc_motors) BLDC_diameter(b)])
+        rotate(-90)
+            BLDC(bldc_motors[$i]);
+
+if($preview)
+    let($show_threads = 1)
+        bldc_motors();

tests/BOM.scad

@@ -20,10 +20,10 @@
 //
 //! BOM and assembly demonstration
 //
+$explode = 1; // Normally set on the command line when generating assembly views with views.py
 include <../core.scad>
 include <../vitamins/sheets.scad>
 use <../vitamins/insert.scad>
-$explode = 1; // Normally set on the command line when generating assembly views with views.py
 
 screw = M3_cap_screw;
 sheet = PMMA3;

tests/LDRs.scad

@@ -16,6 +16,7 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+include <../core.scad>
 include <../vitamins/ldrs.scad>
 
 use <../utils/layout.scad>

tests/PCB.scad

@@ -64,21 +64,25 @@ test_pcb = ["TestPCB", "Test PCB",
         [ 16,  2,   90, "smd_res", RES1206, "1K"],
         [ 19,  2,   90, "smd_res", RES0805, "1K"],
         [ 22,  2,   90, "smd_res", RES0603, "1K"],
+        [ 25,  2,   90, "smd_cap", CAP1206, 1.5],
+        [ 28,  2,   90, "smd_cap", CAP0805, 1.0],
+        [ 31,  2,   90, "smd_cap", CAP0603, 0.7],
+
         [ 10,  10,   0, "2p54header", 4, 1],
         [ 25,  10,   0, "2p54header", 5, 1, false, "blue" ],
         [ 10,  20,   0, "2p54boxhdr", 4, 2],
         [ 10,  30,   0, "2p54socket", 6, 1],
         [ 25,  30,   0, "2p54socket", 4, 1, false, 0, false, "red" ],
-        [ 10,  40,   0, "chip", 10, 5, 1, grey(20)],
-        [  5,  50,   0, "led", LED3mm, "red"],
-        [ 12,  50,   0, "led", LED5mm, "orange"],
-        [ 25,  50,   0, "led", LED10mm, "yellow"],
-        [ 10,  65, 180, "rj45"],
-        [  8,  85, 180, "usb_A"],
+        [ 65,  50,   0, "led", LED3mm, "red"],
+        [ 75,  50,   0, "led", LED5mm, "orange"],
+        [ 90,  50,   0, "led", LED10mm, "yellow"],
+        [ 10,  45, 180, "rj45"],
+        [  8,  65, 180, "usb_A"],
         [  8, 105, 180, "usb_Ax2"],
+        [  7,  85, 180, "molex_usb_Ax1"],
+        [ 8.5,125, 180, "molex_usb_Ax2"],
         [  3, 140, 180, "usb_uA"],
         [  8, 155, 180, "usb_B"],
-        [  8.5, 125, 180, "molex_usb_Ax2"],
         [ 25, 200,   0, "buzzer", 4.5, 8.5],
         [ 25, 218,   0, "buzzer"],
         [  8, 190, 180, "jack"],
@@ -127,6 +131,8 @@ test_pcb = ["TestPCB", "Test PCB",
         [ 52, 200,   0, "pcb", 11, TMC2130 ],
         [ 80, 200,   0, "pdip", 24, "27C32", true, inch(0.6) ],
         [ 80, 170,   0, "pdip", 8, "NE555" ],
+        [ 80, 150,   0, "chip", 10, 5, 1, grey(20)],
+
         [ 52, 206,   0, "2p54socket", 8, 1 ],
         [ 52, 194,   0, "2p54socket", 8, 1, false, 0, false, "red" ],
         [ 50, 220,   0, "standoff",  5, 4.5, 12.5, 2.54],

tests/PCBs.scad

@@ -29,7 +29,12 @@ module pcbs() {
             rotate(90)
                 pcb_assembly(pcbs[$i], 5 + $i, 3);
 
-    translate([0, 110])
+    translate([0, 45])
+        layout([for(p = tiny_pcbs) pcb_length(p)], 3)
+            translate([0, pcb_width(tiny_pcbs[$i]) / 2])
+                 pcb_assembly(tiny_pcbs[$i], 5 + $i, 3);
+
+    translate([0, 120])
         layout([for(p = perfboards) pcb_length(p)], 10)
             translate([0, -pcb_width(perfboards[$i]) / 2])
                 pcb_assembly(perfboards[$i], 5 + $i, 3);

tests/SK_brackets.scad

@@ -22,18 +22,20 @@ include <../vitamins/extrusions.scad>
 
 use <../utils/layout.scad>
 
-module sk_brackets() {
+module sk_brackets(examples = false) {
     screws = [M4_dome_screw, M4_cap_screw, M5_cap_screw, M5_cap_screw];
     nuts = [M4_hammer_nut, M4_sliding_t_nut, M5_sliding_t_nut, undef];
     // channel depth = 6 for 2020 extrusion, 9 for 3030 extrusion
     depths = [6, 6, 9, 0];
     layout([for(s = sk_brackets) 1.5 * sk_size(s)[1]]) {
         sk_bracket_assembly(sk_brackets[$i], screw_type = screws[$i], nut_type = nuts[$i], max_screw_depth = depths[$i]);
-        translate([0, -sk_hole_offset(sk_brackets[$i]) - extrusion_width($i < 2 ? E2020 : E3030) / 2, 0])
-            rotate([0, 90, 0])
-                extrusion($i < 2 ? E2020 : E3030, 20, false);
+
+        if(examples)
+            translate([0, -sk_hole_offset(sk_brackets[$i]) - extrusion_width($i < 2 ? E2020 : E3030) / 2, 0])
+                rotate([0, 90, 0])
+                    extrusion($i < 2 ? E2020 : E3030, 20, false);
     }
 }
 
 if($preview)
-    sk_brackets();
+    sk_brackets(true);

tests/SMDs.scad

@@ -28,6 +28,11 @@ module smds() {
     translate([0, 3])
         layout([for(l = smd_leds) smd_led_size(l).x], 1)
             smd_led(smd_leds[$i], ["green", "blue", "red"][$i % 3]);
+
+    translate([0, 6])
+        layout([for(c = smd_capacitors) smd_cap_size(c).x], 1)
+            let(c = smd_capacitors[$i])
+                smd_capacitor(c, smd_cap_size(c).y * 0.8);
 }
 
 if($preview)

tests/ball_bearings.scad

@@ -16,7 +16,7 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
-
+include <../core.scad>
 use <../utils/layout.scad>
 
 include <../vitamins/ball_bearings.scad>

tests/belts.scad

@@ -25,9 +25,9 @@ use <../utils/layout.scad>
 module belt_test() {
     p2 = [-75, -50];
     p3 = [-75, 100];
-    p4 = [75,  100];
+    p4 = [ 75, 100];
 
-    p5 = [75  + pulley_pr(GT2x20ob_pulley) - pulley_pr(GT2x16_plain_idler), +pulley_pr(GT2x16_plain_idler)];
+    p5 = [ 75 + pulley_pr(GT2x20ob_pulley) - pulley_pr(GT2x16_plain_idler), +pulley_pr(GT2x16_plain_idler)];
     p6 = [-75 + pulley_pr(GT2x20ob_pulley) + pulley_pr(GT2x16_plain_idler), -pulley_pr(GT2x16_plain_idler)];
 
     module pulleys(flip = false) {
@@ -52,19 +52,21 @@ module belt_test() {
         translate(p6) pulley_assembly(GT2x16_plain_idler);
     }
 
-    path = [ [p5.x, p5.y, pulley_pr(GT2x16_plain_idler)],
+    path = [ [-40,  0, 0],
              [p6.x, p6.y, -pulley_pr(GT2x16_plain_idler)],
              [p2.x, p2.y, pulley_pr(GT2x20ob_pulley)],
              [p3.x, p3.y, pulley_pr(GT2x20ob_pulley)],
-             [p4.x, p4.y, pulley_pr(GT2x20ob_pulley)]
+             [p4.x, p4.y, pulley_pr(GT2x20ob_pulley)],
+             [p5.x, p5.y, pulley_pr(GT2x16_plain_idler)],
+             [40,   0, 0],
            ];
 
     belt = GT2x6;
-    belt(belt, path, 80, [0,  0]);
+    belt(belt, path, open = true);
     pulleys();
     translate_z(20)
         hflip() {
-            belt(belt, path, 80, [0,  0], belt_colour = grey(90), tooth_colour = grey(50));
+            belt(belt, path, open = true, belt_colour = grey(90), tooth_colour = grey(50));
             pulleys(flip=true);
         }
 
@@ -72,6 +74,31 @@ module belt_test() {
         layout([for(b = belts) belt_width(b)], 10)
             rotate([0, 90, 0])
                 belt(belts[$i], [[0, 0, 20], [0, 1, 20]], belt_colour = $i%2==0 ? grey(90) : grey(20), tooth_colour = $i%2==0 ? grey(70) : grey(50));
+
+    // new example with open loop - this is a simplified example of the style used for example for the BLV 3D printer
+    pulley = GT2x20ob_pulley;
+    idler = GT2x16_plain_idler;
+    corners = [[-75,-50],[75,100]];
+    carriagepos = [0,0];
+    carriagew = 80;
+
+    points = [
+        [carriagepos.x - carriagew / 2, carriagepos.y, 0],
+        [corners[0].x + belt_pulley_pr(belt, pulley) + belt_pulley_pr(belt, idler), carriagepos.y - belt_pulley_pr(belt, idler), idler],
+        [corners[0].x, corners[0].y, pulley],
+        [corners[0].x, corners[1].y, idler],
+        [corners[1].x, corners[1].y, idler],
+        [corners[1].x, carriagepos.y + belt_pulley_pr(belt, idler), idler],
+        [carriagepos.x + carriagew / 2, carriagepos.y, 0]
+    ];
+    translate_z(-30) {
+        belt(belt, points, open=true, auto_twist=true);
+        for (p = points)
+            if (is_list(p.z))
+                translate([p.x, p.y, 0])
+                    pulley_assembly(p.z);
+    }
+
 }
 
 if($preview)

tests/box_sections.scad

@@ -0,0 +1,30 @@
+//
+// NopSCADlib Copyright Chris Palmer 2021
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+include <../utils/core/core.scad>
+use <../utils/layout.scad>
+
+include <../vitamins/box_sections.scad>
+
+module box_sections() {
+    layout([for(b = box_sections) box_section_size(b).x], 20)
+        box_section(box_sections[$i], 100);
+}
+
+if($preview)
+    box_sections();

tests/displays.scad

@@ -16,6 +16,7 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+include <../core.scad>
 use <../utils/layout.scad>
 
 include <../vitamins/displays.scad>
@@ -23,7 +24,8 @@ use <../vitamins/pcb.scad>
 
 module displays()
     layout([for(d = displays) pcb_length(display_pcb(d))], 10)
-        display(displays[$i]);
+        vflip()
+            display(displays[$i]);
 
 if($preview)
     displays();

tests/extrusion_brackets.scad

@@ -16,13 +16,51 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
-include <../utils/core/core.scad>
+include <../core.scad>
 
-include <../vitamins/extrusion_brackets.scad>
 include <../vitamins/extrusions.scad>
+include <../vitamins/extrusion_brackets.scad>
 include <../vitamins/washers.scad>
 include <../vitamins/nuts.scad>
 
+module inner_bracket_test(bracket, backwards = false)
+    rotate([90, 0, 180]) {
+        extrusion = extrusion_inner_corner_bracket_extrusion(bracket);
+        eWidth = extrusion_width(extrusion);
+        size = extrusion_inner_corner_bracket_size(bracket);
+        tnut = extrusion_inner_corner_bracket_tnut(bracket);
+
+        translate([backwards ? -eWidth : 0, 0])
+            extrusion_inner_corner_bracket(bracket, backwards = backwards);
+
+        translate([-eWidth / 2, 0])
+            rotate([-90, 0, 0])
+                extrusion(extrusion, size.x - nut_thickness(tnut) - extrusion_tab_thickness(extrusion), false, cornerHole = eWidth > 20);
+
+        translate([-eWidth, -eWidth / 2])
+            rotate([0, 90, 0])
+                extrusion(extrusion, eWidth + size.y - nut_thickness(tnut) - extrusion_tab_thickness(extrusion), false, cornerHole = eWidth > 20);
+    }
+
+
+module bracket_test(bracket)
+    rotate([90, 0, 180]) {
+        extrusion = extrusion_corner_bracket_extrusion(bracket);
+        eWidth = extrusion_width(extrusion);
+        size = extrusion_corner_bracket_size(bracket);
+
+        extrusion_corner_bracket_assembly(bracket);
+
+        translate([-eWidth / 2, 0])
+            rotate([-90, 0, 0])
+                extrusion(extrusion, size.y, false, cornerHole = eWidth > 20);
+
+        translate([-eWidth, -eWidth / 2])
+            rotate([0, 90, 0])
+                extrusion(extrusion, eWidth + size.x, false, cornerHole = eWidth > 20);
+    }
+
+
 module extrusion_brackets(examples = false) {
     extrusion_inner_corner_bracket(E20_inner_corner_bracket);
 
@@ -32,34 +70,30 @@ module extrusion_brackets(examples = false) {
     translate([60, 0])
         extrusion_corner_bracket_assembly(E20_corner_bracket);
 
-    eWidth = extrusion_width(E2020);
+    translate([110, 0])
+         extrusion_inner_corner_bracket(E40_inner_corner_bracket);
+
+    translate([140, 0])
+        extrusion_corner_bracket_assembly(E40_corner_bracket);
 
     if(examples) {
-        translate([20, 60, 10]) rotate([90, 0, 180]) {
-            extrusion_inner_corner_bracket(E20_inner_corner_bracket);
+        translate([20, 50, 10])
+            inner_bracket_test(E20_inner_corner_bracket, true);
 
-            translate([-eWidth / 2, 0, 0])
-                rotate([-90, 0, 0])
-                    extrusion(E2020, 20, false);
+        translate([20, 80, 10])
+            inner_bracket_test(E20_inner_corner_bracket);
 
-            translate([-eWidth, -eWidth / 2, 0])
-                rotate([0, 90, 0])
-                    extrusion(E2020, 40, false);
-        }
+        translate([20, 120, 10])
+            bracket_test(E20_corner_bracket);
 
-        translate([100, 60, 10]) rotate([90, 0, 180]) {
-            extrusion_corner_bracket_assembly(E20_corner_bracket);
+        translate([100, 70, 10])
+            inner_bracket_test(E40_inner_corner_bracket);
 
-            translate([-eWidth / 2, 0, 0])
-                rotate([-90, 0, 0])
-                    extrusion(E2020, 30, false);
-
-            translate([-eWidth, -eWidth / 2, 0])
-                rotate([0, 90, 0])
-                    extrusion(E2020, 50, false);
-        }
+        translate([100, 130, 10])
+            bracket_test(E40_corner_bracket);
     }
 }
 
 if($preview)
-    extrusion_brackets(true);
+    let($show_threads = true)
+        extrusion_brackets(true);

tests/extrusions.scad

@@ -21,9 +21,24 @@ use <../utils/layout.scad>
 
 include <../vitamins/extrusions.scad>
 
+gap = 10;
+
 module extrusions()
-    layout([for(e = extrusions) extrusion_width(e)], 10)
-        extrusion(extrusions[$i], 80, cornerHole = extrusion_width(extrusions[$i]) > 20);
+    layout([for(e = extrusions) is_list(e[0]) ? extrusion_width(e[0]) : extrusion_width(e)], gap)
+        let(e = extrusions[$i])
+            if(is_list(e[0])) {
+                list = e;
+                heights = [for(e = list) extrusion_height(e)];
+                l = len(heights) - 1;
+                offset = (heights * [for(i = [0 : l]) 1] + l * gap) / 2;
+                translate([0, -offset])
+                    rotate(90)
+                        layout(heights, gap)
+                            rotate(-90)
+                                extrusion(list[$i], 80, cornerHole = extrusion_width(list[$i]) > 20);
+            }
+            else
+                extrusion(e, 80, cornerHole = extrusion_width(e) > 20);
 
 if ($preview)
     extrusions();

tests/geared_steppers.scad

@@ -16,12 +16,13 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+include <../core.scad>
 include <../vitamins/geared_steppers.scad>
 
 use <../utils/layout.scad>
 
 module geared_steppers()
-    layout([for(g = geared_steppers) gs_diameter(g)], 5)
+    layout([for(g = geared_steppers) max(gs_diameter(g), gs_pitch(g) + gs_lug_w(g) / 2)], 5)
         geared_stepper(geared_steppers[$i]);
 
 geared_steppers();

tests/green_terminals.scad

@@ -16,6 +16,7 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+include <../core.scad>
 use <../utils/layout.scad>
 
 include <../vitamins/green_terminals.scad>

tests/hygrometer.scad

@@ -16,6 +16,7 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+include <../core.scad>
 use <../vitamins/hygrometer.scad>
 
 if($preview)

tests/microview.scad

@@ -16,6 +16,7 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+include <../core.scad>
 use <../vitamins/microview.scad>
 
 microview(!$preview);

tests/nuts.scad

@@ -52,6 +52,12 @@ module nuts() {
 
             if(n == M5_nut)
                 sliding_t_nut(M5_sliding_t_nut);
+
+            if(n == M6_nut)
+                sliding_t_nut(M6_sliding_t_nut);
+
+            if(n == M8_nut)
+                sliding_t_nut(M8_sliding_ball_t_nut);
         }
 
         translate([0, 80]) {

tests/o_ring.scad

@@ -16,6 +16,7 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+include <../core.scad>
 use <../vitamins/o_ring.scad>
 
 module o_rings()

tests/pin_headers.scad

@@ -64,8 +64,9 @@ module pin_headers() {
             pin_socket(pin_headers[$i], 3, 3, right_angle = true);
     }
 
-    for(i = [0, 1], p = [5, 2][i], j = [0 , 1]) {
-        h = [jst_ph_header, jst_xh_header][j];
+    headers = [jst_zh_header, jst_ph_header, jst_xh_header];
+    for(i = [0, 1], p = [5, 2][i], j = [0 : len(headers) - 1]) {
+        h = headers[j];
         translate([-20 * (i + 1), 0 + j * 40])
             jst_xh_header(h, p);
 

tests/press_fit.scad

@@ -16,8 +16,8 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
-
-include <../printed/press_fit.scad>
+include <../core.scad>
+use <../printed/press_fit.scad>
 
 module press_fits()
 {

tests/rails.scad

@@ -22,21 +22,28 @@ include <../vitamins/rails.scad>
 use <../utils/layout.scad>
 use <../vitamins/nut.scad>
 
+length = 200;
 sheet = 3;
 pos = 1; //[-1 : 0.1 : 1]
 
+function rail_carriages(rail) = [for(c = carriages) if(carriage_rail(c) == rail) c];
+
 module rails()
-    layout([for(l = carriages) carriage_width(l)], 20)
+    layout([for(r = rails) carriage_width(rail_carriages(r)[0])], 10)
         rotate(-90) {
-            carriage = carriages[$i];
-            rail = carriage_rail(carriage);
-            length = 200;
+            rail = rails[$i];
+            carriages = rail_carriages(rail);
+            carriage = carriages[0];
             screw = rail_screw(rail);
             nut = screw_nut(screw);
             washer = screw_washer(screw);
 
             rail_assembly(carriage, length, pos * carriage_travel(carriage, length) / 2, $i<2 ? grey(20) : "green", $i<2 ? grey(20) : "red");
 
+            if(len(carriages) > 1)
+                translate([-carriage_travel(carriages[1], length) / 2, 0])
+                    carriage(carriages[1]);
+
             rail_screws(rail, length, sheet + nut_thickness(nut, true) + washer_thickness(washer));
 
             rail_hole_positions(rail, length, 0)

tests/screws.scad

@@ -16,6 +16,10 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+
+// Extra countersink depth
+sink = 0; // [0 : 0.05: 1.0]
+
 include <../core.scad>
 
 module polysink_stl() {
@@ -32,9 +36,9 @@ module polysink_stl() {
             let(s = cs_screws[i])
                 translate([i * 20, 0]) {
                     translate_z(size.z)
-                        screw_polysink(s, 2 * size.z + 1);
+                        screw_polysink(s, 2 * size.z + 1, sink = sink);
 
-                    screw_polysink(s, 2 * size.z + 1, alt = true);
+                    screw_polysink(s, 2 * size.z + 1, alt = true, sink = sink);
                 }
     }
 }
@@ -44,7 +48,7 @@ module screws() {
         for(x = [0 : len(screw_lists[y]) -1]) {
             screw = screw_lists[y][x];
             if(screw) {
-                 length = screw_head_type(screw) == hs_grub ? 6
+                 length = screw_head_type(screw) == hs_grub ? screw_radius(screw) * 4
                         : screw_radius(screw) <= 1.5 ? 10
                         : screw_max_thread(screw) ? screw_longer_than(screw_max_thread(screw) + 5)
                         : 30;

tests/servo_motors.scad

@@ -0,0 +1,31 @@
+//
+// NopSCADlib Copyright Chris Palmer 2021
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+include <../core.scad>
+use <../utils/layout.scad>
+
+include <../vitamins/servo_motors.scad>
+
+module servo_motors()
+    layout([for(s = servo_motors) servo_motor_width(s)], 10) let(s = servo_motors[$i]) {
+        rotate(-90)             // Show the keyway
+            servo_motor(s);
+    }
+
+if($preview)
+    servo_motors();

tests/stepper_motors.scad

@@ -22,12 +22,12 @@ include <../vitamins/stepper_motors.scad>
 use <../utils/layout.scad>
 
 module stepper_motors()
-    layout([for(s = stepper_motors) NEMA_width(s)], 5, no_offset = true) let(m = stepper_motors[$i]) {
+    layout([for(s = stepper_motors) NEMA_width(s)], 5, no_offset = false) let(m = stepper_motors[$i]) {
         rotate(180)
-            NEMA(m, 0, m == NEMA17P || m == NEMA17M || m == NEMA17M8);
+            NEMA(m, 0, in([NEMA17P, NEMA17M, NEMA17M8, NEMA8, NEMA8BH], m));
 
         translate_z(4)
-            NEMA_screws(m, M3_pan_screw, n = $i, earth = $i > 4 ? undef : $i - 1);
+            NEMA_screws(m, M3_pan_screw, n = $i - 2, earth = $i > 6 ? undef : $i - 3);
     }
 
 if($preview)

utils/core/bom.scad

@@ -29,7 +29,7 @@
 //! This is to prevent the global BOM page becoming too wide in large projects by having it include just the major assemblies.
 //!
 //! The example below shows how to define a vitamin and incorporate it into an assembly with sub-assemblies and make an exploded view.
-//! The resulting flat BOM is shown but heirachical BOMs are also generated for real projects.
+//! The resulting flat BOM is shown but hierarchical BOMs are also generated for real projects.
 //!
 //! If the code to make an STL or DXF is made a child of the `stl()` or `dxf()` module then the STL or DXF will be used in the assembly views generated by `views.py` instead of generating
 //! it with code.

utils/core/clip.scad

@@ -18,7 +18,7 @@
 //
 
 //
-//! Construct arbirarily large box to partition 3D space and clip objects, useful for creating cross sections to see the inside when debugging.
+//! Construct arbitrarily large box to partition 3D space and clip objects, useful for creating cross sections to see the inside when debugging.
 //!
 //! Original version by Doug Moen on the OpenSCAD forum
 //

utils/core/polyholes.scad

@@ -28,12 +28,12 @@
 //! large increase in the number of facets.
 //! When set to 1 the polygons alternate each layer, when set higher the rotation takes `twist + 1` layers to repeat.
 //! A small additional rotation is added to make the polygon rotate one more side over the length of the hole to make it appear round when
-//! veiwed end on.
+//! viewed end on.
 //!
 //! When `twist` is set the resulting cylinder is extended by `eps` at each end so that the exact length of the hole can be used without
 //! leaving a scar on either surface.
 //
-function sides(r, n = undef) = is_undef(n) ? max(round(4 * r), 3) : n ? max(n, 3) : r2sides(r); //! Optimium number of sides for specified radius
+function sides(r, n = undef) = is_undef(n) ? max(round(4 * r), 3) : n ? max(n, 3) : r2sides(r); //! Optimum number of sides for specified radius
 function corrected_radius(r, n = undef)   = r / cos(180 / sides(r, n));                         //! Adjusted radius to make flats lie on the circle
 function corrected_diameter(d, n = undef) = 2 * corrected_radius(d / 2 , n);                    //! Adjusted diameter to make flats lie on the circle
 

utils/core/teardrops.scad

@@ -26,7 +26,7 @@
 //
 module teardrop(h, r, center = true, truncate = true, chamfer = 0, chamfer_both_ends = true, plus = false) { //! For making horizontal holes that don't need support material, set `truncate = false` to make traditional RepRap teardrops that don't even need bridging
     module teardrop_2d(r, truncate) {
-        er = layer_height / 2 - eps;    // Extrustion edge radius
+        er = layer_height / 2 - eps;    // Extrusion edge radius
         R = plus ? r + er : r;          // Corrected radius
         offset = plus ? -er : 0;        // Offset inwards
         hull()

utils/core_xy.scad

@@ -51,15 +51,20 @@ function coreXY_lower_tooth_colour(type)    = type[8]; //! Colour of the lower b
 // relative to the anchor pulley so that the belts align properly
 function coreXY_drive_pulley_x_alignment(type) = //! Belt alignment offset of the drive pulley relative to the anchor pulley
     (pulley_od(coreXY_drive_pulley(type)) - pulley_od(coreXY_toothed_idler(type))) / 2;
+
 function coreXY_coincident_separation(type) = //! Value of x, y separation to make y-carriage pulleys coincident
     [ -coreXY_plain_idler_offset(type).x, -(pulley_od(coreXY_plain_idler(type)) + pulley_od(coreXY_toothed_idler(type)))/2, 0 ];
+
 function coreXY_plain_idler_offset(type)    = //! Offset of y-carriage plain idler
     [ (pulley_od(coreXY_plain_idler(type)) + pulley_od(coreXY_drive_pulley(type))) / 2 + coreXY_drive_pulley_x_alignment(type), pulley_od(coreXY_plain_idler(type))/2, 0 ];
+
 function coreXY_toothed_idler_offset(type)  = //! offset of y-carriage toothed idler
     [ 0, -pulley_pr(coreXY_toothed_idler(type)), 0 ];
+
 // helper functions for positioning idlers when the stepper motor drive pulley is offset
 function coreXY_drive_toothed_idler_offset(type) = //! Offset of toothed drive idler pulley
     [ 0, coreXY_drive_pulley_x_alignment(type), 0 ];
+
 function coreXY_drive_plain_idler_offset(type) = //! Offset of plain drive idler pulley
     [ coreXY_plain_idler_offset(type).x, -(pulley_od(coreXY_plain_idler(type)) + pulley_od(coreXY_drive_pulley(type))) / 2, 0 ];
 
@@ -86,7 +91,7 @@ module coreXY_half(type, size, pos, separation_y = 0, x_gap = 0, plain_idler_off
 
     // toothed idler for offset stepper motor drive pulley
     p3t_type = coreXY_toothed_idler(type);
-    p3t = [ -size.x / 2 + (drive_pulley_offset.x > 0 ? 0 : 2*coreXY_drive_pulley_x_alignment(type)),
+    p3t = [ -size.x / 2 + (drive_pulley_offset.x > 0 ? 0 : 2 * coreXY_drive_pulley_x_alignment(type)),
             size.y / 2 + coreXY_drive_pulley_x_alignment(type) + drive_pulley_offset.y
     ];
 
@@ -102,11 +107,11 @@ module coreXY_half(type, size, pos, separation_y = 0, x_gap = 0, plain_idler_off
             size.y / 2 - pulley_od(p3p_type) / 2 - pulley_od(p3d_type) / 2 + drive_pulley_offset.y
     ];
 
-    // dummy pulleys for y separation
-    p5_type = p4_type;
-    p5 = [ pos.x - size.x / 2, -size.y / 2 + pos.y + separation_y / 2 ];
-    p6_type = p0_type;
-    p6 = [ pos.x - size.x / 2, -size.y / 2 + pos.y - separation_y / 2 ];
+    // Start and end points
+    start_p = [ pos.x - size.x / 2 + x_gap / 2, -size.y / 2 + pos.y - separation_y / 2, 0 ];
+    end_p   = [ pos.x - size.x / 2 - x_gap / 2, -size.y / 2 + pos.y + separation_y / 2, 0 ];
+
+    //p6_type = p0_type;
 
     module show_pulleys(show_pulleys) {// Allows the pulley colour to be set for debugging
         if (is_list(show_pulleys))
@@ -119,16 +124,21 @@ module coreXY_half(type, size, pos, separation_y = 0, x_gap = 0, plain_idler_off
     show_pulleys(show_pulleys) {
         translate(p0)
             pulley_assembly(p0_type); // y-carriage toothed pulley
+
         translate(p1)
             pulley_assembly(p1_type); // bottom right toothed idler pulley
+
         translate(p2)
             pulley_assembly(p2_type); // bottom left anchor toothed idler pulley
+
         translate(p3d)
             hflip(hflip)
                 pulley_assembly(p3d_type); // top left stepper motor drive pulley
+
         if (drive_pulley_offset.x) { // idler pulleys for offset stepper motor drive pulley
             translate(p3t)
                 pulley_assembly(p3t_type); // toothed idler
+
             translate(p3p)
                 pulley_assembly(p3p_type); // plain idler
         }
@@ -157,41 +167,38 @@ module coreXY_half(type, size, pos, separation_y = 0, x_gap = 0, plain_idler_off
         [ p3t.x, p3t.y, pulley_od(p3t_type) / 2 ],
         [ p4.x, p4.y, -pulley_od(p4_type) / 2 ]
     ];
-    path1 = [ // use eps for corner radius to get sharp corners so this part of the belt is deleted by the gap
-        [ p5.x, p5.y, eps ],
-        [ p6.x, p6.y, eps ]
-    ];
 
     belt = coreXY_belt(type);
 
     path0 = drive_pulley_offset.x == 0 ? concat(path0a, path0b) : drive_pulley_offset.x > 0 ? concat(path0a, path0c) : concat(path0a, path0d);
-    path = separation_y == 0 ? path0 : concat(path0, path1);
+    path = concat([start_p], path0, [end_p]);
 
     belt(type = belt,
         points = path,
-        gap = [ x_gap + eps, abs(separation_y) + 2 ],
-        gap_pos = [ pos.x - size.x / 2, pos.y - size.y / 2 + belt_pitch_height(belt) - belt_thickness(belt) / 2 ],
+        open = true,
         belt_colour  = lower_belt ? coreXY_lower_belt_colour(type) : coreXY_upper_belt_colour(type),
         tooth_colour = lower_belt ? coreXY_lower_tooth_colour(type) : coreXY_upper_tooth_colour(type));
 }
 
-module coreXY(type, size, pos, separation, x_gap, plain_idler_offset = 0, upper_drive_pulley_offset, lower_drive_pulley_offset, show_pulleys = false) { //! Wrapper module to draw both belts of a coreXY setup
+module coreXY(type, size, pos, separation, x_gap, plain_idler_offset = 0, upper_drive_pulley_offset, lower_drive_pulley_offset, show_pulleys = false, left_lower = false) { //! Wrapper module to draw both belts of a coreXY setup
     translate([size.x / 2 - separation.x / 2, size.y / 2, -separation.z / 2]) {
         // lower belt
-        hflip()
+        hflip(!left_lower)
             explode(25)
-                coreXY_half(type, size, [size.x - pos.x - separation.x, pos.y], separation.y, x_gap, plain_idler_offset, [-lower_drive_pulley_offset.x, lower_drive_pulley_offset.y], show_pulleys, lower_belt = true, hflip = true);
+                coreXY_half(type, size, [size.x - pos.x - separation.x/2 - (left_lower ? x_gap : 0), pos.y], separation.y, x_gap, plain_idler_offset, [-lower_drive_pulley_offset.x, lower_drive_pulley_offset.y], show_pulleys, lower_belt = true, hflip = true);
+
         // upper belt
         translate([separation.x, 0, separation.z])
-            explode(25)
-                coreXY_half(type, size, [pos.x, pos.y], separation.y, x_gap, plain_idler_offset, upper_drive_pulley_offset, show_pulleys, lower_belt = false, hflip=false);
+            hflip(left_lower)
+                explode(25)
+                    coreXY_half(type, size, [pos.x + separation.x/2 + (left_lower ? x_gap : 0), pos.y], separation.y, x_gap, plain_idler_offset, upper_drive_pulley_offset, show_pulleys, lower_belt = false, hflip = false);
     }
 }
 
-module coreXY_belts(type, carriagePosition, coreXYPosBL, coreXYPosTR, separation, x_gap = 20, upper_drive_pulley_offset = [0, 0], lower_drive_pulley_offset = [0, 0], show_pulleys = false) { //! Draw the coreXY belts
+module coreXY_belts(type, carriagePosition, coreXYPosBL, coreXYPosTR, separation, x_gap = 20, upper_drive_pulley_offset = [0, 0], lower_drive_pulley_offset = [0, 0], show_pulleys = false, left_lower = false) { //! Draw the coreXY belts
     assert(coreXYPosBL.z == coreXYPosTR.z);
 
     coreXYSize = coreXYPosTR - coreXYPosBL;
     translate(coreXYPosBL)
-        coreXY(type, coreXYSize, [carriagePosition.x - coreXYPosBL.x + separation.x / 2, carriagePosition.y - coreXYPosBL.y], separation = separation, x_gap = x_gap, plain_idler_offset = 0, upper_drive_pulley_offset = upper_drive_pulley_offset, lower_drive_pulley_offset = lower_drive_pulley_offset, show_pulleys = show_pulleys);
+        coreXY(type, coreXYSize, [carriagePosition.x - coreXYPosBL.x, carriagePosition.y - coreXYPosBL.y], separation = separation, x_gap = x_gap, plain_idler_offset = 0, upper_drive_pulley_offset = upper_drive_pulley_offset, lower_drive_pulley_offset = lower_drive_pulley_offset, show_pulleys = show_pulleys, left_lower = left_lower);
 }

utils/gears.scad

@@ -135,4 +135,4 @@ function involute_worm_profile(m, pa = 20, clearance = undef) = //! Calculate wo
     let(tooth = involute_rack_tooth_profile(m),
         pitch = PI * m,
         y_min = min([for(p = tooth) p.y])
-    ) [for(p = tooth) [p.x - pitch / 2, p.y - y_min, 0]];   // Offset to be positive in y, centred in x and add 0 z ordintate
+    ) [for(p = tooth) [p.x - pitch / 2, p.y - y_min, 0]];   // Offset to be positive in y, centred in x and add 0 z coordinate

utils/maths.scad

@@ -88,6 +88,7 @@ function scale(v) = let(s = is_list(v) ? v : [v, v, v]) //!  Generate a 4x4 matr
                           [0,   0,   0,   1]
                         ];
 
+function vec2(v) = [v.x, v.y]; //! Return a 2 vector with the first two elements of `v`
 function vec3(v) = [v.x, v.y, v.z]; //! Return a 3 vector with the first three elements of `v`
 function vec4(v) = [v.x, v.y, v.z, 1]; //! Return a 4 vector with the first three elements of `v`
 function transform(v, m) = vec3(m * [v.x, v.y, v.z, 1]); //! Apply 4x4 transform to a 3 vector by extending it and cropping it again
@@ -153,3 +154,36 @@ function circle_intersect(c1, r1, c2, r2) =     //! Calculate one point where tw
         d = norm(v),                            // Distance between centres
         a = atan2(v.z, v.x) - acos((sqr(d) + sqr(r2) - sqr(r1)) / (2 * d * r2)) // Cosine rule to find angle from c2
      ) c2 + r2 * [cos(a), 0, sin(a)];           // Point on second circle
+
+function map(v, func) = [ for (e = v) func(e) ]; //! make a new vector where the func function argument is applied to each element of the vector v
+function mapi(v, func) = [ for (i = [0:len(v)-1]) func(i,v[i]) ]; //! make a new vector where the func function argument is applied to each element of the vector v. The func will get the index number as first argument, and the element as second argument.
+function reduce(v, func, unity) = let ( r = function(i,val) i == len(v) ? val : r(i + 1, func(val, v[i])) ) r(0, unity); //! reduce a vector v to a single entity by applying the func function recursively to the reduced value so far and the next element, starting with unity as the initial reduced value
+function sumv(v) = reduce(v, function(a, b) a + b, 0); //! sum a vector of values that can be added with "+"
+
+function xor(a,b) = (a && !b) || (!a && b);     //! Logical exclusive OR
+function cuberoot(x)= sign(x)*abs(x)^(1/3);
+
+function quadratic_real_roots(a, b, c) =        //! Returns real roots of a quadratic equation, biggest first. Returns empty list if no real roots
+    let(2a = 2 * a,
+        2c = 2 * c,
+        det = b^2 - 2a * 2c
+    ) det < 0 ? [] :
+        let(r = sqrt(det),
+            x1 = b < 0 ? 2c / (-b + r) : (-b - r) / 2a,
+            x2 = b < 0 ? (-b + r) / 2a : 2c / (-b - r)
+        ) [x2, x1];
+
+function cubic_real_roots(a, b, c, d) = //! Returns real roots of cubic equation
+    let(b = b / a,
+        c = c / a,
+        d = d / a,
+        inflection = -b / 3,
+        p = c - b^2 / 3,
+        q = 2 * b^3 / 27 - b * c / 3 + d,
+        det = q^2 / 4 + p^3 / 27,
+        roots = !p && !q ? 1 : nearly_zero(det) ? 2 :  det < 0 ? 3 : 1,
+        r = sqrt(det),
+        x = cuberoot(-q / 2 - r) + cuberoot(-q / 2 + r)
+    ) roots == 1 ? [x] :
+      roots == 2 ? [3 * q /p + inflection, -3 * q / p / 2 + inflection] :
+      [for(i = [0 : roots - 1]) 2 * sqrt(-p / 3) * cos(acos(3 * q * sqrt(-3 / p) / p / 2) - i * 120) + inflection];

utils/rounded_polygon.scad

@@ -24,6 +24,7 @@
 //! Because the tangents need to be calculated to find the length these can be calculated separately and re-used when drawing to save calculating them twice.
 //
 include <../utils/core/core.scad>
+use <../utils/maths.scad>
 
 function circle_tangent(p1, p2) = //! Compute the clockwise tangent between two circles represented as [x,y,r]
     let(
@@ -36,56 +37,66 @@ function circle_tangent(p1, p2) = //! Compute the clockwise tangent between two
         v = [cos(theta), sin(theta)]
     )[ p1 + r1 * v, p2 + r2 * v ];
 
-function rounded_polygon_tangents(points) = //! Compute the straight sections needed to draw and to compute the lengths
-    let(len = len(points))
-        [for(i = [0 : len - 1])
-            let(ends = circle_tangent(points[i], points[(i + 1) % len]))
-                for(end = [0, 1])
-                    ends[end]];
+function rounded_polygon_arcs(points, tangents) = //! Compute the arcs at the points, for each point [angle, rotate_angle, length]
+    let(
+        len = len(points)
+    ) [ for (i = [0: len-1])
+        let(
+            p1 = vec2(tangents[(i - 1 + len) % len][1]),
+            p2 = vec2(tangents[i][0]),
+            p = vec2(points[i]),
+            v1 = p1 - p,
+            v2 = p2 - p,
+            sr = points[i][2],
+            r = abs(sr),
+            a = r < 0.001 ? 0 : let( aa = acos((v1 * v2) / sqr(r)) ) cross(v1, v2) * sign(sr) <= 0 ? aa : 360 - aa,
+            l = PI * a * r / 180,
+            v0 = [r, 0],
+            v = let (
+                vv = norm(v0 - v2) < 0.001 ? 0 : abs(v2.y) < 0.001 ? 180 :
+                        let( aa = acos((v0 * v2) / sqr(r)) ) cross(v0, v2) * sign(sr) <= 0 ? aa : 360 - aa
+            ) sr > 0 ? 360 - vv : vv - a
+        ) [a, v, l]
+    ];
 
-function sumv(v, i = 0, sum = 0) = i == len(v) ? sum : sumv(v, i + 1, sum + v[i]);
+function rounded_polygon_tangents(points) = //! Compute the straight sections between a point and the next point, for each section [start_point, end_point, length]
+    let(len = len(points))
+    [ for(i = [0 : len - 1])
+        let(ends = circle_tangent(points[i], points[(i + 1) % len]))
+            [ends[0], ends[1], norm(ends[0] - ends[1])]
+    ];
 
 // the cross product of 2D vectors is the area of the parallelogram between them. We use the sign of this to decide if the angle is bigger than 180.
 function rounded_polygon_length(points, tangents) = //! Calculate the length given the point list and the list of tangents computed by ` rounded_polygon_tangents`
     let(
-      len = len(points),
-      indices = [0 : len - 1],
-      straights = [for(i = indices) norm(tangents[2 * i] - tangents[2 * i + 1])],
-      arcs = [for(i = indices) let(p1 = tangents[2 * i + 1],
-                                   p2 = tangents[(2 * i + 2) % (2 * len)],
-                                   corner = points[(i + 1) % len],
-                                   c = [corner.x, corner.y],
-                                   v1 = p1 - c,
-                                   v2 = p2 - c,
-                                   r = abs(corner.z),
-                                   a = acos((v1 * v2) / sqr(r))) r ? PI * (cross(v1, v2) <= 0 ? a : 360 - a) * r / 180 : 0]
-     )
-    sumv(concat(straights, arcs));
+        arcs = rounded_polygon_arcs(points, tangents)
+    ) sumv( map( concat(tangents, arcs), function(e) e[2] ) );
 
 module rounded_polygon(points, _tangents = undef) { //! Draw the rounded polygon from the point list, can pass the tangent list to save it being calculated
     len = len(points);
     indices = [0 : len - 1];
     tangents = _tangents ? _tangents : rounded_polygon_tangents(points);
 
-    difference(convexity = points) {
+    difference() {
         union() {
-            for(i = indices)
+            for(i = indices, last = (i - 1 + len) % len)
                 if(points[i][2] > 0)
                     hull() {
-                        translate([points[i].x, points[i].y])
+                        translate(vec2(points[i]))
                             circle(points[i][2]);
-                        polygon([tangents[(2 * i - 1 + 2 * len) % (2 * len)], tangents[2 * i], [points[i].x, points[i].y]]);
+
+                        polygon([vec2(tangents[last][1]), vec2(tangents[i][0]), vec2(points[i])]);
                     }
 
-            polygon(tangents, convexity = points);
+            polygon([for(t = tangents) each(vec2(t))], convexity = points);
         }
-        for(i = indices)
+        for(i = indices, last = (i - 1 + len) % len)
             if(points[i][2] < 0)
                 hull() {
-                    translate([points[i].x, points[i].y])
+                    translate(vec2(points[i]))
                         circle(-points[i][2]);
 
-                    polygon([tangents[(2 * i - 1 + 2 * len) % (2 *len)], tangents[2 * i], [points[i].x, points[i].y]]);
+                    polygon([vec2(tangents[last][1]), vec2(tangents[i][0]), vec2(points[i])]);
                 }
      }
 }

utils/sweep.scad

@@ -18,7 +18,7 @@
 //
 
 //
-//! Utility to generate a polhedron by sweeping a 2D profile along a 3D path and utilities for generating paths.
+//! Utility to generate a polyhedron by sweeping a 2D profile along a 3D path and utilities for generating paths.
 //!
 //! The initial orientation is the Y axis of the profile points towards the initial center of curvature, Frenet-Serret style.
 //! Subsequent rotations use the minimum rotation method.

utils/thread.scad

@@ -50,6 +50,7 @@ function thread_profile(h, crest, angle, overlap = 0.1) = //! Create thread prof
         [[-base / 2, -overlap, 0], [-crest / 2, h, 0], [crest / 2, h, 0], [base / 2, -overlap, 0]];
 
 module thread(dia, pitch, length, profile, center = true, top = -1, bot = -1, starts = 1, solid = true, female = false, colour = undef) { //! Create male or female thread, ends can be tapered, chamfered or square
+    assert(is_undef(colour) || is_list(colour), "Thread colour must be in [r, g, b] form");
     //
     // Apply colour if defined
     //
@@ -155,7 +156,7 @@ module thread(dia, pitch, length, profile, center = true, top = -1, bot = -1, st
                                         translate([0, offset])
                                             square([r, len]);
 
-                                        translate([0, bot_chamfer_h])
+                                        translate([0, offset + bot_chamfer_h])
                                             square([r + h + overlap, len - top_chamfer_h - bot_chamfer_h]);
                                     }
                                     if(!solid)
@@ -190,7 +191,8 @@ module female_metric_thread(d, pitch, length, center = true, top = -1, bot = -1,
 }
 
 function metric_coarse_pitch(d) //! Convert metric diameter to pitch
-    = d == 1.6 ? 0.35  // M1.6
+    = d == 1.4 ? 0.3   // M1.4
+    : d == 1.6 ? 0.35  // M1.6
                : [0.4, // M2
                   0.45,// M2.5
                   0.5, // M3

utils/tube.scad

@@ -25,7 +25,9 @@ include <../utils/core/core.scad>
 module ring(or, ir) //! Create a ring with specified external and internal radii
         difference() {
             circle4n(or);
-            circle4n(ir);
+
+            if(ir > 0)
+                circle4n(ir);
         }
 
 module tube(or, ir, h, center = true) //! Create a tube with specified external and internal radii and height `h`
@@ -69,7 +71,7 @@ module woven_tube(or, ir, h, center= true, colour = grey(30), colour2, warp = 2,
     }
 }
 
-module rectangular_tube(size, center = true, thickness = 1, fillet = 0.5) { //! Create a retangular tube with filleted corners
+module rectangular_tube(size, center = true, thickness = 1, fillet = 0.5) { //! Create a rectangular tube with filleted corners
     extrude_if(size.z, center = center)
         difference() {
             rounded_square([size.x, size.y], fillet);

vitamins/belt.scad

@@ -18,19 +18,29 @@
 //
 
 //
-//! Models timing belt running over toothed or smooth pulleys and calculates an accurate length.
-//! Only models 2D paths, so not crossed belt core XY!
+//! Models timing belt running in a path over toothed or smooth pulleys and calculates an accurate length.
+//! Only models 2D paths, belt may twist to support crossed belt core XY and other designs where the belt twists!
+//!
+//! By default the path is a closed loop. An open loop can be specified by specifying `open=true`, and in that case the start and end points are not connected, leaving the loop open.
+//!
+//! To get a 180 degree twist of the loop, you can use the `twist` argument. `Twist` can be a single number, and in that case the belt will twist after
+//! the position with that number. Alternatively `twist` can be a list of boolean values with a boolean for each position; the belt will then twist after
+//! the position that have a `true` value in the `twist` list. If the path is specified with pulley/idler types, then you can use `auto_twist=true`; in
+//! that case the belt will automatically twist so the back of the belt always runs against idlers and the tooth side runs against pulleys. If you use
+//! `open=true` then you might also use `start_twist=true` to let the belt start the part with the back side out.
+//!
+//! The path must be specified as a list of positions. Each position should be either a vector with `[x, y, pulley]` or `[x, y, r]`. A pulley is a type from
+//! `pulleys.scad`, and correct radius and angle will automatically be calculated. Alternatively a radius can be specified directly.
 //!
 //! To make the back of the belt run against a smooth pulley on the outside of the loop specify a negative pitch radius.
-//!
-//! By default the path is a closed loop but a gap length and position can be specified to make open loops.
-//! To draw the gap its XY position is specified by `gap_pos`. `gap_pos.z` can be used to specify a rotation if the gap is not at the bottom of the loop.
+//! Alternatively you can just specify smooth pulleys in the path, and it will then happen automatically.
 //!
 //! Individual teeth are not drawn, instead they are represented by a lighter colour.
 //
 include <../utils/core/core.scad>
 use <../utils/rounded_polygon.scad>
 use <../utils/maths.scad>
+use <pulley.scad>
 
 function belt_pitch(type)        = type[1]; //! Pitch in mm
 function belt_width(type)        = type[2]; //! Width in mm
@@ -41,47 +51,102 @@ function belt_pitch_height(type) = type[5] + belt_tooth_height(type); //! Offset
 function belt_pitch_to_back(type) = belt_thickness(type) - belt_pitch_height(type); //! Offset of the back from the pitch radius
 //
 // We model the belt path at the pitch radius of the pulleys and the pitch line of the belt to get an accurate length.
-// The belt is then drawn by offseting each side from the pitch line.
 //
-module belt(type, points, gap = 0, gap_pos = undef, belt_colour = grey(20), tooth_colour = grey(50)) { //! Draw a belt path given a set of points and pitch radii where the pulleys are. Closed loop unless a gap is specified
+module belt(type, points, belt_colour = grey(20), tooth_colour = grey(50), open = false, twist = undef, auto_twist = false, start_twist = false) { //! Draw a belt path given a set of points and pitch radii where the pulleys are. Closed loop unless open is specified
     width = belt_width(type);
     pitch = belt_pitch(type);
     thickness = belt_thickness(type);
+
+    info = _belt_points_info(type, points, open, twist, auto_twist, start_twist);
+    dotwist = info[0]; // array of booleans, true if a twist happen after the position
+    twisted = info[1]; // array of booleans, true if the belt is twisted at the position
+    pointsx = info[2]; // array of [x,y,r], r is negative if left-angle (points may have pulleys as third element, but pointsx have radii)
+    tangents = info[3];
+    arcs = info[4];
+    length = ceil(_belt_length(info, open) / pitch) * pitch;
+
     part = str(type[0],pitch);
-    vitamin(str("belt(", no_point(part), "x", width, ", ", points, arg(gap, 0), arg(gap_pos, undef), "): Belt ", part," x ", width, "mm x ", length, "mm"));
+    vitamin(str("belt(", no_point(part), "x", width, ", ", pointsx, "): Belt ", part," x ", width, "mm x ", length, "mm"));
 
     len = len(points);
 
-    tangents = rounded_polygon_tangents(points);
-
-    length = ceil((rounded_polygon_length(points, tangents) - (is_list(gap) ? gap.x + gap.y : gap)) / pitch) * pitch;
-
-    module shape() rounded_polygon(points, tangents);
-
-    ph = belt_pitch_height(type);
     th = belt_tooth_height(type);
-    module gap()
-        if(gap)
-            translate([gap_pos.x, gap_pos.y])
-                rotate(is_undef(gap_pos.z) ? 0 : gap_pos.z)
-                    translate([0, ph - thickness / 2])
-                        square(is_list(gap) ? [gap.x, gap.y + thickness + eps] : [gap, thickness + eps], center = true);
+    ph = belt_pitch_height(type);
+    module beltp() translate([ph - th, -width / 2]) square([th, width]);
+    module beltb() translate([ph - thickness, -width / 2]) square([thickness - th, width]);
 
-    color(belt_colour)
-        linear_extrude(width, center = true)
-            difference() {
-                offset(-ph + thickness ) shape();
-                offset(-ph + th) shape();
-                gap();
-            }
+    for (i = [0 : len - (open ? 2 : 1)]) {
+        p1 = tangents[i].x;
+        p2 = tangents[i].y;
+        v = p2-p1;
+        a =  atan(v.y / v.x) - (v.x < 0 ? 180 : 0); //a2(p2-p1);
+        l = norm(v);
+        translate(p1) rotate([-90, 0, a - 90]) {
+            twist = dotwist[i] ? 180 : 0;
+            mirrored = twisted[i] ? 1 : 0;
+            color(tooth_colour) linear_extrude(l, twist = twist) mirror([mirrored, 0, 0]) beltp();
+            color(belt_colour)  linear_extrude(l, twist = twist) mirror([mirrored, 0, 0]) beltb();
+        }
+    }
 
-    color(tooth_colour)
-        linear_extrude(width, center = true)
-            difference() {
-                offset(-ph + th) shape();
-                offset(-ph) shape();
-                gap();
-            }
+    for (i = [(open ? 1 : 0) : len - (open ? 2 : 1)]) {
+        p = pointsx[i];
+        arc = arcs[i];
+        translate([p.x, p.y]) rotate([0, 0, arc[1]]) {
+            mirrored = xor(twisted[i], p[2] < 0) ? 0 : 1;
+            color(tooth_colour) rotate_extrude(angle = arc[0]) translate([abs(p[2]), 0, 0]) mirror([mirrored, 0, 0]) beltp();
+            color(belt_colour)  rotate_extrude(angle = arc[0]) translate([abs(p[2]), 0, 0]) mirror([mirrored, 0, 0]) beltb();
+        }
+    }
 }
 
-function belt_length(points, gap = 0) = rounded_polygon_length(points, rounded_polygon_tangents(points)) - gap; //! Compute belt length given path and optional gap
+function _belt_points_info(type, points, open, twist, auto_twist, start_twist) = //! Helper function that calculates [twist, istwisted, points, tangents, arcs]
+let(
+    len = len(points),
+    isleft = function(i) let(
+            p = vec2(points[i]),
+            p0 = vec2(points[(i - 1 + len) % len]),
+            p1 = vec2(points[(i + 1) % len])
+        ) cross(p-p0,p1-p) > 0,
+    dotwist = function(i, istwisted) let( in = (i + 1) % len )
+        is_list(twist) ? twist[i] :
+        !is_undef(twist) ? i == twist :
+        open && is_list(points[in][2]) && auto_twist ? !pulley_teeth(points[in][2]) && !xor(isleft(in), istwisted) :
+        false,
+    twisted = [
+        for (
+            i = 0,
+            istwisted = start_twist,
+            twist = dotwist(i, istwisted),
+            nexttwisted = xor(twist, istwisted);
+            i < len;
+            i = i + 1,
+            istwisted = nexttwisted,
+            twist = dotwist(i, istwisted),
+            nexttwisted = xor(twist, istwisted)
+        ) [twist, istwisted] ],
+    pointsx = mapi(points, function(i, p) !is_list(p[2]) ? p : [p.x, p.y, let( // if p[2] is not a list it is just r, otherwise it is taken to be a pulley and we calculate r
+            isleft = isleft(i),
+            r = belt_pulley_pr(type, p[2], twisted = !xor(pulley_teeth(p[2]), xor(isleft, twisted[i][1])))
+        ) isleft ? -r : r ] ),
+    tangents = rounded_polygon_tangents(pointsx),
+    arcs = rounded_polygon_arcs(pointsx, tangents)
+) [ [ for (t = twisted) t[0] ], [ for (t = twisted) t[1] ], pointsx, tangents, arcs];
+
+function belt_pulley_pr(type, pulley, twisted=false) = //! Pitch radius. Default it expects the belt tooth to be against a toothed pulley an the backside to be against a smooth pulley (an idler). If `twisted` is true, the the belt is the other way around.
+    let(
+        thickness = belt_thickness(type),
+        ph = belt_pitch_height(type)
+    ) pulley_teeth(pulley)
+        ? pulley_pr(pulley) + (twisted ? thickness - ph : 0 )
+        : pulley_ir(pulley) + (twisted ? ph : thickness - ph );
+
+
+function belt_length(type, points, open = false) = _belt_length(_belt_points_info(type, points, open), open); //! Compute belt length given path
+
+function _belt_length(info, open) = let(
+    len = len(info[0]),
+    d = open ? 1 : 0,
+    tangents = slice(info[3], 0, len - d) ,
+    arcs = slice(info[4], d, len - d)
+) sumv( map( concat(tangents, arcs), function(e) e[2] ));

vitamins/bldc_motor.scad

@@ -0,0 +1,288 @@
+//
+// NopSCADlib Copyright Chris Palmer 2021
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+//
+//!  Brushless DC electric motor
+//
+include <NopSCADlib/core.scad>
+
+use <NopSCADlib/vitamins/rod.scad>
+use <NopSCADlib/utils/thread.scad>
+use <NopSCADlib/utils/tube.scad>
+
+
+function BLDC_diameter(type)                    = type[1]; //! Diameter of motor
+function BLDC_height(type)                      = type[2]; //! Height of motor including boss, if any, but excluding prop shaft
+function BLDC_shaft_diameter(type)              = type[3]; //! shaft diameter
+function BLDC_shaft_length(type)                = type[4]; //! Total shaft length
+function BLDC_shaft_offset(type)                = type[5]; //! shaft offset from base
+function BLDC_body_colour(type)                 = type[6]; //! Body colour
+function BLDC_base_diameter(type)               = type[7]; //! Base diameter
+function BLDC_base_height_1(type)               = type[8]; //! Base height 1
+function BLDC_base_height_2(type)               = type[9]; //! Base height 2
+function BLDC_base_hole_diameter(type)          = type[10]; //! Base hole diameter
+function BLDC_base_holes(type)                  = type[11]; //! Base holes
+function BLDC_base_open(type)                   = type[12]; //! Base open
+function BLDC_wire_diameter(type)               = type[13]; //! Wire diameter
+function BLDC_side_colour(type)                 = type[14]; //! Side colour
+function BLDC_bell_diameter(type)               = type[15]; //! Bell diameter
+function BLDC_bell_height_1(type)               = type[16]; //! Bell height 1
+function BLDC_bell_height_2(type)               = type[17]; //! Bell height 2
+function BLDC_bell_hole_diameter(type)          = type[18]; //! Bell hole diameter
+function BLDC_bell_holes(type)                  = type[19]; //! Bell holes
+function BLDC_bell_spokes(type)                 = type[20]; //! Bell spoke count
+function BLDC_boss_diameter(type)               = type[21]; //! Boss diameter
+function BLDC_boss_height(type)                 = type[22]; //! Boss height
+function BLDC_prop_shaft_length(type)           = type[23]; //! Prop shaft length, including threaded section
+function BLDC_prop_shaft_diameter(type)         = type[24]; //! Diameter of unthreaded portion of prop shaft
+function BLDC_prop_shaft_thread_length(type)    = type[25]; //! Length of threaded section of prop shaft
+function BLDC_prop_shaft_thread_diameter(type)  = type[26]; //! Diameter of threaded section of prop shaft
+
+bldc_cap_colour  = grey(50);
+bldc_shaft_colour = grey(90);
+bldc_bearing_colour = grey(80);
+
+module BLDC(type) { //! Draw specified BLDC motor
+    vitamin(str("BLDC(", type[0], "): Brushless DC motor ", type[0]));
+
+    body_colour = BLDC_body_colour(type);
+    side_colour = BLDC_side_colour(type);
+    body_diameter = BLDC_diameter(type);
+    wall_thickness = 1;
+
+    height = BLDC_height(type) - BLDC_boss_height(type);
+
+    module feet(base_diameter) {
+        holes = BLDC_base_holes(type);
+        hole_count = is_list(holes) ? len(holes) : 4;
+        for(i = [0 : 1 : hole_count - 1]) {
+            spacing = is_list(holes) ? holes[i] : holes;
+            radius = base_diameter / 2 - spacing / 2;
+            rotate(i * 360 / hole_count + (hole_count == 4 ? 45 : 0))
+                difference() {
+                    hull() {
+                        circle(r = radius);
+                        translate([-spacing / 2, 0])
+                            circle(r = radius);
+                    }
+                    translate([-spacing / 2, 0])
+                        circle(d = BLDC_base_hole_diameter(type));
+                }
+        }
+    }
+
+    module cutout(d1, d2, r, h) {
+        translate_z(-eps)
+            linear_extrude(h + 2 * eps)
+                hull() {
+                    translate([d1 / 2, 0])
+                        circle(r = r);
+                    translate([d2 / 2, -r])
+                        square([eps, 2 * r]);
+                }
+    }
+
+    module cutout2(d1, r1, d2, r2, h) {
+        translate_z(-eps)
+            linear_extrude(h + 2 * eps)
+                hull() {
+                    translate([d1 / 2, 0])
+                        circle(r = r1);
+                    translate([d2 / 2, 0])
+                        circle(r = r2);
+                }
+    }
+
+    module base() {
+        base_diameter = BLDC_base_diameter(type);
+        h1 = BLDC_base_height_1(type);
+        h2 = BLDC_base_height_2(type);
+        color(body_colour)
+            if (BLDC_base_open(type)) {
+                linear_extrude(h1)
+                    difference() {
+                        union() {
+                            feet(base_diameter);
+                            circle(d = 3 * BLDC_shaft_diameter(type));
+                        }
+                        circle(d = 2 * BLDC_shaft_diameter(type));
+                    }
+                translate_z(h1)
+                    cylinder(d = 3 * BLDC_shaft_diameter(type), h = h2);
+            } else {
+                difference() {
+                    union() {
+                        render(convexity = 8)
+                            linear_extrude(h1)
+                                difference() {
+                                    circle(d = base_diameter);
+                                    circle(d = 2 * BLDC_shaft_diameter(type));
+                                    BLDC_base_screw_positions(type)
+                                        circle(d = BLDC_base_hole_diameter(type));
+                                }
+                        rotate_extrude()
+                            polygon([ [base_diameter / 2, 0], [body_diameter / 2, h1], [body_diameter / 2, h1+h2], [body_diameter / 2 - wall_thickness, h1 + h2], [body_diameter / 2 - wall_thickness, h1], [base_diameter / 2, h1] ]);
+                    }
+                r = body_diameter > 40 ? 2 : body_diameter * PI / (8 * 3);
+                if (body_diameter > 40) {
+                    r = 2;
+                    // cutout for wires
+                    translate_z(h2 /2)
+                        cutout(base_diameter, body_diameter, 6, h1);
+                    for (a = [90, 180, 270])
+                        rotate(a) {
+                            cutout(base_diameter - 2 * r, body_diameter, r, h1 + h2 / 2);
+                            for (b = [-90 / 4, 90 / 4])
+                                rotate(b)
+                                    cutout(base_diameter - 5 * r, body_diameter, r, h1 + h2 / 2);
+                        }
+                } else {
+                    r = body_diameter * PI / (8 * 3);
+                    for (a = [0, 90, 180, 270])
+                        rotate(a)
+                            cutout(base_diameter, body_diameter, r, h1);
+                }
+            }
+        }
+        color(bldc_bearing_colour)
+            translate_z(0.25)
+                tube(or = BLDC_shaft_diameter(type), ir = BLDC_shaft_diameter(type) / 2, h = h1, center = false);
+
+        if (show_threads)
+            BLDC_base_screw_positions(type)
+                female_metric_thread(BLDC_base_hole_diameter(type), metric_coarse_pitch(BLDC_base_hole_diameter(type)), h1, center = false, colour = body_colour);
+
+        wire_diameter = BLDC_wire_diameter(type);
+        for (i = [0 : 2])
+            color(wire_diameter >= 3 ? ["yellow", grey(20), "red"][i] : grey(20))
+                translate([body_diameter / 5, (i - 1) * wire_diameter, wire_diameter / 2 + 0.25 + (body_diameter > 40 ? h2/2 : 0)])
+                    rotate([0, 90, 0])
+                        cylinder(r = wire_diameter / 2, h = body_diameter / 2, center = false);
+
+    } // end module base
+
+    module bell() {
+        bell_diameter = BLDC_bell_diameter(type);
+        h1 = BLDC_bell_height_1(type);
+        h2 = BLDC_bell_height_2(type);
+        gap = BLDC_base_open(type) ? 0 : height > 20 ? 0.5 : 0.25;
+        side_length = height - h2 - h1 - gap - BLDC_base_height_1(type) - BLDC_base_height_2(type);
+
+        color(body_colour) {
+            translate_z(height - h2) {
+                difference() {
+                    union() {
+                        top_thickness = min(h2, 2);
+                        render(convexity = 8)
+                            translate_z(h2 - top_thickness)
+                                linear_extrude(top_thickness)
+                                    difference() {
+                                        circle(d = bell_diameter);
+                                        if (BLDC_shaft_length(type) > height)
+                                            circle(d = BLDC_shaft_diameter(type));
+                                        BLDC_bell_screw_positions(type)
+                                            circle(d = BLDC_bell_hole_diameter(type));
+                                    }
+                        rotate_extrude()
+                            polygon([ [bell_diameter/2, h2], [body_diameter/2, 0], [body_diameter/2, -h1], [body_diameter/2 - wall_thickness, -h1], [body_diameter/2 - wall_thickness, 0], [bell_diameter/2, h2 - top_thickness] ]);
+                    }
+                    spoke_count = BLDC_bell_spokes(type);
+                    if (spoke_count % 4 == 0) {
+                        r = body_diameter > 40 ? body_diameter / 15 : 2.5;
+                        for (a = [0, 90, 180, 270])
+                            rotate(a) {
+                                cutout(bell_diameter + 2 * r, body_diameter, r, h2);
+                                rotate(45) {
+                                    cutout(bell_diameter, body_diameter, r, h2);
+                                }
+                            }
+                    } else {
+                        r1 = bell_diameter * PI / (spoke_count * 3);
+                        r2 = body_diameter * PI / (spoke_count * 3);
+                        for (i = [0 : 1 : spoke_count - 1])
+                            rotate(i * 360 / spoke_count)
+                                cutout2(bell_diameter, r1, body_diameter, r2, h2);
+                    }
+                } // end difference
+            } // end translate
+
+            if (BLDC_boss_height(type))
+                translate_z(height)
+                    tube(or = BLDC_boss_diameter(type)/2, ir = BLDC_shaft_diameter(type)/2, h = BLDC_boss_height(type), center = false);
+
+        } // end colour
+
+        color(BLDC_prop_shaft_thread_length(type) == 0 ? bldc_shaft_colour : body_colour)
+            if (BLDC_prop_shaft_diameter(type))
+                translate_z(height + BLDC_boss_height(type)) {
+                    thread_diameter = BLDC_prop_shaft_thread_diameter(type);
+                    unthreaded_length = BLDC_prop_shaft_length(type) - BLDC_prop_shaft_thread_length(type);
+                    cylinder(d=BLDC_prop_shaft_diameter(type), h = unthreaded_length);
+                    if (BLDC_prop_shaft_thread_length(type) > 0)
+                        translate_z(unthreaded_length)
+                            if (show_threads)
+                                male_metric_thread(thread_diameter, metric_coarse_pitch(thread_diameter), BLDC_prop_shaft_thread_length(type), center = false);
+                            else
+                                cylinder(d = thread_diameter, h = BLDC_prop_shaft_thread_length(type));
+                }
+        color(side_colour)
+            translate_z(height - h2 - h1  -side_length)
+                tube(body_diameter/2, body_diameter/2 - wall_thickness, side_length, center = false);
+
+        if (show_threads)
+            translate_z(height)
+                BLDC_bell_screw_positions(type)
+                    vflip()
+                        female_metric_thread(BLDC_bell_hole_diameter(type), metric_coarse_pitch(BLDC_bell_hole_diameter(type)), h2, center = false, colour = body_colour);
+    } // end module bell
+
+    base();
+    bell();
+
+    color(bldc_shaft_colour)
+        translate_z(-BLDC_shaft_offset(type) - eps)
+            not_on_bom()
+                rod(d = BLDC_shaft_diameter(type), l = BLDC_shaft_length(type), center = false);
+
+}
+
+module BLDC_screw_positions(holes, n = 4) { //! Screw positions utility function
+    hole_count = is_list(holes) ? len(holes) : 4;
+    for($i = [0 : min(n, hole_count) - 1]) {
+        spacing = is_list(holes) ? holes[$i] : holes;
+        rotate($i * 360 / hole_count)
+            translate([spacing / 2, 0])
+                rotate(-$i * 90)
+                    children();
+    }
+}
+
+module BLDC_base_screw_positions(type, n = 4) { //! Positions children at the base screw holes
+    if (BLDC_base_holes(type))
+        rotate(is_list(BLDC_base_holes(type)) && len(BLDC_base_holes(type)) == 3 ? 180 : 45)
+            BLDC_screw_positions(BLDC_base_holes(type), n)
+                children();
+}
+
+module BLDC_bell_screw_positions(type, n = 4) { //! Positions children at the bell screw holes
+    if (BLDC_bell_holes(type))
+        rotate(is_list(BLDC_bell_holes(type)) && len(BLDC_bell_holes(type)) == 3 ? 30 : 0)
+            BLDC_screw_positions(BLDC_bell_holes(type), n)
+                children();
+}

vitamins/bldc_motors.scad

@@ -0,0 +1,37 @@
+//
+// NopSCADlib Copyright Chris Palmer 2021
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+//
+// Brushless DC electric motors
+//
+//                                     shaft  shaft shaft      body   base             holes                 base            side  bell             holes          boss  prop shaft   thread
+//                      diameter height diam length offset   colour   diam   h1    h2  diam position         open  wire    colour  diam   h1    h1  d  pos   spokes  d  h  length diam  length  diam
+BLDC0603  = ["BLDC0603",    9.0,  8,      1,  15.5,     1, crimson,    10,   1,  1.5,  1.4, [6,6,6],        true,  0.8, grey(20),    9,   1,    1,  0,  0,       5,  0, 0,     0,   0,      0,     0];
+BLDC0802  = ["BLDC0802",   11.5,  9.5,  1.5,    12,   0.5, grey(20),    9,   1,    2,  1.6, [6,6,6],        true,  1.0, grey(20),   11,   2, 0.75,  0,  0,       3,  0, 0,     0,   0,      0,     0];
+BLDC1105  = ["BLDC1105",   14.0, 11.75, 1.5,    11,     0, grey(90), 12.5, 1.6,  1.4,  2,    9,             true,  1.0, grey(90),   12,   1,    1,  2, [5,5],    4,  0, 0,     0,   0,      0,     0];
+BLDC1306  = ["BLDC1306",  17.75, 14.5,    2,    14,     0, crimson,    16, 1.5,    1,  2,   12,            false,  1.0, grey(20),   12,   1,    1,  0,  0,       6,  8, 1,  11.5,   5,    6.5,     5];
+BLDC1804  = ["BLDC1804",   23.0, 12,      2,    11,     0, grey(20),   19, 2.5,  1.5,  2,   12,            false,  1.5, grey(20),   18,   1,  2.5,  0,  0,       6,  9, 1,    12,   5,      6,     5];
+BLDC2205  = ["BLDC2205",   28.0, 17.25,   3,    16,     0, crimson,    26,   2,    3,  3,   [19,16,19,16], false,  1.6, grey(20), 22.5,   1, 3.75,  0,  0,       6,  0, 0,    14,   5,      9,     5];
+BLDC2212  = ["BLDC2212",   28.0, 27,      3,    26,     0, grey(20),   23,   4,    2,  3,   [19,16,19,16], false,  2.0, grey(20),   18,   2,    4,  0,  0,       6,  0, 0,    14,   8,      7,     6];
+BLDC3548  = ["BLDC3548",   35.0, 45,      5,  65.5,     1, gold,       32,   7,    1,  3,   [25,19,25,19], false,  3.0, grey(20),   32,   2,    4,2.5, [16,16,16],6,12, 3.4,   0,   0,      0,     0];
+BLDC4250  = ["BLDC4250",   42.5, 48,      5,    70,    20, crimson,    38,   4,    6,  3,   25,            false,  3.5, grey(20),   28,   3,    6,  3, 17,       8, 12, 2,     0,   0,      0,     0];
+
+bldc_motors = [BLDC0603, BLDC0802, BLDC1105, BLDC1306, BLDC1804, BLDC2205, BLDC2212, BLDC3548, BLDC4250];
+
+use <bldc_motor.scad>

vitamins/blower.scad

@@ -28,6 +28,7 @@ use <screw.scad>
 function blower_length(type)      = type[2]; //! Length of enclosing rectangle
 function blower_width(type)       = type[3]; //! Width of enclosing rectangle
 function blower_depth(type)       = type[4]; //! Height
+function blower_size(type)        = [blower_length(type), blower_width(type), blower_depth(type)]; //! Size
 function blower_bore(type)        = type[5]; //! The air intake hole diameter
 function blower_screw(type)       = type[6]; //! The type of screws needed
 function blower_hub(type)         = type[7]; //! Rotor hub diameter

vitamins/box_section.scad

@@ -0,0 +1,58 @@
+//
+// NopSCADlib Copyright Chris Palmer 2021
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+//
+//! Box sections.
+//
+include <../utils/core/core.scad>
+include <../utils/tube.scad>
+
+include <../vitamins/sheets.scad>
+
+function box_section_material(type)  = type[1]; //! Material description
+function box_section_size(type)      = type[2]; //! Size
+function box_section_thickness(type) = type[3]; //! Wall thickness
+function box_section_fillet(type)    = type[4]; //! Fillet
+function box_section_colour(type)    = type[5]; //! Colour
+function box_section_colour2(type)   = type[6]; //! Colour2, for woven box section
+function box_section_is_woven(type)  = !is_undef(type[6]); //! Box section is woven, eg carbon fiber
+
+module box_section(type, length, center = true) {
+    vitamin(str("box_section(", type[0], arg(length, 15), "): ", box_section_material(type), ", length ", length, "mm"));
+
+    size = box_section_size(type);
+    thickness = box_section_thickness(type);
+
+    if (box_section_is_woven(type))
+        translate_z(center ? 0 : length / 2) {
+            rotate([0, -90, 90])
+                for (z = [-size.y / 2, size.y / 2 - thickness])
+                    translate_z(z)
+                        woven_sheet(CF1, thickness, box_section_colour(type), box_section_colour2(type), length, size.x)
+                            square([length, size.x], center=true);
+            rotate([0, -90, 0])
+                for (z = [-size.x / 2, size.x / 2 - thickness])
+                    translate_z(z)
+                        woven_sheet(CF1, thickness, box_section_colour(type), box_section_colour2(type), length, size.y)
+                            square([length, size.y], center=true);
+        }
+    else
+        color(box_section_colour(type))
+            rectangular_tube([size.x, size.y, length], center, thickness, box_section_fillet(type));
+}

vitamins/box_sections.scad

@@ -0,0 +1,30 @@
+//
+// NopSCADlib Copyright Chris Palmer 2021
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+//
+// Box sections
+//
+AL12x8x1 =  ["AL12x8x1",  "Aluminium rectangular box section 12mm x 8mm x 1mm",     [12, 8],  1, 0.5, silver, undef];
+AL20x20x2 = ["AL20x20x2", "Aluminium rectangular box section 20mm x 20mm x 2mm",    [20, 20], 2, 0.5, silver, undef];
+CF10x10x1 = ["CF10x10x1", "Carbon fiber rectangular box section 10mm x 10mm x 1mm", [10, 10], 1, 0.5, grey(35), grey(20)];
+
+
+box_sections = [AL12x8x1, AL20x20x2, CF10x10x1];
+
+use <box_section.scad>

vitamins/cable_strip.scad

@@ -20,7 +20,7 @@
 //
 //! A strip of polypropylene used with ribbon cable to make a cable flexible in one direction only.
 //!
-//! Modelled with a Bezier spline, which is not quite the same as a minimum energy curve but very close, epecially
+//! Modelled with a Bezier spline, which is not quite the same as a minimum energy curve but very close, especially
 //! near the extreme positions, where the model needs to be accurate.
 //!
 //! When the sides are constrained then a circular model is more accurate.

vitamins/camera.scad

@@ -25,7 +25,7 @@ use <pcb.scad>
 
 function camera_pcb(type)           = type[2]; //! The PCB part of the camera
 function camera_lens_offset(type)   = type[3]; //! Offset of the lens center from the PCB centre
-function camera_lens(type)          = type[4]; //! Stack of lens parts, can be round, rectanular or rounded rectangular, with optional tapered aperture
+function camera_lens(type)          = type[4]; //! Stack of lens parts, can be round, rectangular or rounded rectangular, with optional tapered aperture
 function camera_connector_pos(type) = type[5]; //! The flex connector block for the camera itself's position
 function camera_connector_size(type)= type[6]; //! The flex connector block for the camera itself's size
 

vitamins/display.scad

@@ -18,7 +18,7 @@
 //
 
 //
-//! LCD dispays.
+//! LCD displays.
 //
 include <../utils/core/core.scad>
 

vitamins/displays.scad

@@ -53,7 +53,7 @@ LCDS7282BPCB = ["", "", 85, 36, 1.65, 0, 2.56, 0, "green", false, [[-2.5, -2.5],
       []];
 
 LCDS7282B = ["LCDS7282B", "LCD display S-7282B", 73.6, 28.7, 9.6, LCDS7282BPCB,
-          [-2.5, 0, 0],                             // pcb offst
+          [-2.5, 0, 0],                             // pcb offset
           [[-64.5 / 2, -14.5 / 2], [64.5 / 2, 14.5 / 2, 0.6]],              // aperture
           [],                                       // touch screen
           0,                                        // thread length