Updated readme

Updated images and readme.

readme.md

@@ -28,27 +28,28 @@ See [usage](docs/usage.md) for requirements, installation instructions and a usa
 <tr><td> <a href = "#Components">Components</a> </td><td> <a href = "#Psus">Psus</a> </td><td> <a href = "#Fan_guard">Fan_guard</a> </td><td> <a href = "#Offset">Offset</a> </td><td></td></tr>
 <tr><td> <a href = "#D_connectors">D_connectors</a> </td><td> <a href = "#Pulleys">Pulleys</a> </td><td> <a href = "#Fixing_block">Fixing_block</a> </td><td> <a href = "#Quadrant">Quadrant</a> </td><td></td></tr>
 <tr><td> <a href = "#Displays">Displays</a> </td><td> <a href = "#Rails">Rails</a> </td><td> <a href = "#Flat_hinge">Flat_hinge</a> </td><td> <a href = "#Round">Round</a> </td><td></td></tr>
-<tr><td> <a href = "#Extrusions">Extrusions</a> </td><td> <a href = "#Ring_terminals">Ring_terminals</a> </td><td> <a href = "#Foot">Foot</a> </td><td> <a href = "#Rounded_cylinder">Rounded_cylinder</a> </td><td></td></tr>
-<tr><td> <a href = "#Fans">Fans</a> </td><td> <a href = "#Rockers">Rockers</a> </td><td> <a href = "#Handle">Handle</a> </td><td> <a href = "#Rounded_polygon">Rounded_polygon</a> </td><td></td></tr>
-<tr><td> <a href = "#Fuseholder">Fuseholder</a> </td><td> <a href = "#Rod">Rod</a> </td><td> <a href = "#Pcb_mount">Pcb_mount</a> </td><td> <a href = "#Sector">Sector</a> </td><td></td></tr>
-<tr><td> <a href = "#Geared_steppers">Geared_steppers</a> </td><td> <a href = "#Screws">Screws</a> </td><td> <a href = "#Psu_shroud">Psu_shroud</a> </td><td> <a href = "#Sweep">Sweep</a> </td><td></td></tr>
-<tr><td> <a href = "#Green_terminals">Green_terminals</a> </td><td> <a href = "#Scs_bearing_blocks">Scs_bearing_blocks</a> </td><td> <a href = "#Ribbon_clamp">Ribbon_clamp</a> </td><td> <a href = "#Thread">Thread</a> </td><td></td></tr>
-<tr><td> <a href = "#Hot_ends">Hot_ends</a> </td><td> <a href = "#Sealing_strip">Sealing_strip</a> </td><td> <a href = "#Screw_knob">Screw_knob</a> </td><td> <a href = "#Tube">Tube</a> </td><td></td></tr>
-<tr><td> <a href = "#Hygrometer">Hygrometer</a> </td><td> <a href = "#Sheets">Sheets</a> </td><td> <a href = "#Socket_box">Socket_box</a> </td><td></td><td></td></tr>
-<tr><td> <a href = "#Iecs">Iecs</a> </td><td> <a href = "#Sk_brackets">Sk_brackets</a> </td><td> <a href = "#Ssr_shroud">Ssr_shroud</a> </td><td></td><td></td></tr>
-<tr><td> <a href = "#Inserts">Inserts</a> </td><td> <a href = "#Spades">Spades</a> </td><td> <a href = "#Strap_handle">Strap_handle</a> </td><td></td><td></td></tr>
-<tr><td> <a href = "#Jack">Jack</a> </td><td> <a href = "#Spools">Spools</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Kp_pillow_blocks">Kp_pillow_blocks</a> </td><td> <a href = "#Springs">Springs</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Ldrs">Ldrs</a> </td><td> <a href = "#Ssrs">Ssrs</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Leadnuts">Leadnuts</a> </td><td> <a href = "#Stepper_motors">Stepper_motors</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Leds">Leds</a> </td><td> <a href = "#Toggles">Toggles</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Light_strips">Light_strips</a> </td><td> <a href = "#Transformers">Transformers</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Linear_bearings">Linear_bearings</a> </td><td> <a href = "#Tubings">Tubings</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Mains_sockets">Mains_sockets</a> </td><td> <a href = "#Variacs">Variacs</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Meter">Meter</a> </td><td> <a href = "#Veroboard">Veroboard</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Microswitches">Microswitches</a> </td><td> <a href = "#Washers">Washers</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Microview">Microview</a> </td><td> <a href = "#Wire">Wire</a> </td><td></td><td></td><td></td></tr>
-<tr><td> <a href = "#Modules">Modules</a> </td><td> <a href = "#Zipties">Zipties</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Extrusion_brackets">Extrusion_brackets</a> </td><td> <a href = "#Ring_terminals">Ring_terminals</a> </td><td> <a href = "#Foot">Foot</a> </td><td> <a href = "#Rounded_cylinder">Rounded_cylinder</a> </td><td></td></tr>
+<tr><td> <a href = "#Extrusions">Extrusions</a> </td><td> <a href = "#Rockers">Rockers</a> </td><td> <a href = "#Handle">Handle</a> </td><td> <a href = "#Rounded_polygon">Rounded_polygon</a> </td><td></td></tr>
+<tr><td> <a href = "#Fans">Fans</a> </td><td> <a href = "#Rod">Rod</a> </td><td> <a href = "#Pcb_mount">Pcb_mount</a> </td><td> <a href = "#Sector">Sector</a> </td><td></td></tr>
+<tr><td> <a href = "#Fuseholder">Fuseholder</a> </td><td> <a href = "#Screws">Screws</a> </td><td> <a href = "#Psu_shroud">Psu_shroud</a> </td><td> <a href = "#Sweep">Sweep</a> </td><td></td></tr>
+<tr><td> <a href = "#Geared_steppers">Geared_steppers</a> </td><td> <a href = "#Scs_bearing_blocks">Scs_bearing_blocks</a> </td><td> <a href = "#Ribbon_clamp">Ribbon_clamp</a> </td><td> <a href = "#Thread">Thread</a> </td><td></td></tr>
+<tr><td> <a href = "#Green_terminals">Green_terminals</a> </td><td> <a href = "#Sealing_strip">Sealing_strip</a> </td><td> <a href = "#Screw_knob">Screw_knob</a> </td><td> <a href = "#Tube">Tube</a> </td><td></td></tr>
+<tr><td> <a href = "#Hot_ends">Hot_ends</a> </td><td> <a href = "#Sheets">Sheets</a> </td><td> <a href = "#Socket_box">Socket_box</a> </td><td></td><td></td></tr>
+<tr><td> <a href = "#Hygrometer">Hygrometer</a> </td><td> <a href = "#Sk_brackets">Sk_brackets</a> </td><td> <a href = "#Ssr_shroud">Ssr_shroud</a> </td><td></td><td></td></tr>
+<tr><td> <a href = "#Iecs">Iecs</a> </td><td> <a href = "#Spades">Spades</a> </td><td> <a href = "#Strap_handle">Strap_handle</a> </td><td></td><td></td></tr>
+<tr><td> <a href = "#Inserts">Inserts</a> </td><td> <a href = "#Spools">Spools</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Jack">Jack</a> </td><td> <a href = "#Springs">Springs</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Kp_pillow_blocks">Kp_pillow_blocks</a> </td><td> <a href = "#Ssrs">Ssrs</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Ldrs">Ldrs</a> </td><td> <a href = "#Stepper_motors">Stepper_motors</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Leadnuts">Leadnuts</a> </td><td> <a href = "#Toggles">Toggles</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Leds">Leds</a> </td><td> <a href = "#Transformers">Transformers</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Light_strips">Light_strips</a> </td><td> <a href = "#Tubings">Tubings</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Linear_bearings">Linear_bearings</a> </td><td> <a href = "#Variacs">Variacs</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Mains_sockets">Mains_sockets</a> </td><td> <a href = "#Veroboard">Veroboard</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Meter">Meter</a> </td><td> <a href = "#Washers">Washers</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Microswitches">Microswitches</a> </td><td> <a href = "#Wire">Wire</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Microview">Microview</a> </td><td> <a href = "#Zipties">Zipties</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Modules">Modules</a> </td><td></td><td></td><td></td><td></td></tr>
 </table>
 
 ---
@@ -589,6 +590,54 @@ LCD dispays.
 |   1 | ```display(SSD1963_4p3)``` |  LCD display SSD1963 4.3" |
 
 
+<a href="#top">Top</a>
+
+---
+<a name="Extrusion_brackets"></a>
+## Extrusion_brackets
+Brackets for joining extrusions at a corner.
+
+
+[vitamins/extrusion_brackets.scad](vitamins/extrusion_brackets.scad) Object definitions.
+
+[vitamins/extrusion_bracket.scad](vitamins/extrusion_bracket.scad) Implementation.
+
+[tests/extrusion_brackets.scad](tests/extrusion_brackets.scad) Code for this example.
+
+### Properties
+| Function | Description |
+|:--- |:--- |
+| ```extrusion_corner_bracket_base_thickness(type)``` | Thickness of base of bracket |
+| ```extrusion_corner_bracket_hole_offset(type)``` | Hole offset from corner |
+| ```extrusion_corner_bracket_side_thickness(type)``` | Thickness of side of bracket |
+| ```extrusion_corner_bracket_size(type)``` | Size of bracket |
+| ```extrusion_inner_corner_bracket_size(type)``` | Size of inner bracket |
+
+### Modules
+| Module | Description |
+|:--- |:--- |
+| ```extrusion_corner_bracket(type)``` | Corner bracket for extrusion |
+| ```extrusion_corner_bracket_assembly(type, part_thickness = 2, screw_type = M4_cap_screw, nut_type = M4_sliding_t_nut, max_screw_depth = 6)``` | Assembly with fasteners in place |
+| ```extrusion_corner_bracket_hole_positions(type)``` | Place children at hole positions |
+| ```extrusion_inner_corner_bracket(type, grub_screws = true)``` | Inner corner bracket for extrusion |
+
+![extrusion_brackets](tests/png/extrusion_brackets.png)
+
+### Vitamins
+| Qty | Module call | BOM entry |
+| ---:|:--- |:---|
+|   1 | ```extrusion(E2020, 20, false)``` |  Extrusion E2020 x 20mm |
+|   1 | ```extrusion(E2020, 30, false)``` |  Extrusion E2020 x 30mm |
+|   1 | ```extrusion(E2020, 40, false)``` |  Extrusion E2020 x 40mm |
+|   1 | ```extrusion(E2020, 50, false)``` |  Extrusion E2020 x 50mm |
+|   2 | ```extrusion_corner_bracket(E20_corner_bracket)``` |  Extrusion corner bracket 20 |
+|   2 | ```extrusion_inner_corner_bracket(E20_inner_corner_bracket, true)``` |  Extrusion inner corner bracket 4.5 |
+|   1 | ```extrusion_inner_corner_bracket(E20_inner_corner_bracket, false)``` |  Extrusion inner corner bracket 4.5 |
+|   4 | ```sliding_t_nut(M4_sliding_t_nut)``` |  Nut M4 sliding T |
+|   4 | ```screw(M4_cap_screw, 8)``` |  Screw M4 cap x  8mm |
+|   4 | ```washer(M4_washer)``` |  Washer  M4 x 9mm x 0.8mm |
+
+
 <a href="#top">Top</a>
 
 ---
@@ -620,21 +669,21 @@ Aluminium  extrusion.
 ### Modules
 | Module | Description |
 |:--- |:--- |
-| ```extrusion(type, length, cornerHole = false)``` | Draw the specified extrusion |
+| ```extrusion(type, length, center = false, cornerHole = false)``` | Draw the specified extrusion |
 
 ![extrusions](tests/png/extrusions.png)
 
 ### Vitamins
 | Qty | Module call | BOM entry |
 | ---:|:--- |:---|
-|   1 | ```extrusion(E2020, 80)``` |  Extrusion E2020 x 80mm |
-|   1 | ```extrusion(E2040, 80)``` |  Extrusion E2040 x 80mm |
-|   1 | ```extrusion(E2060, 80)``` |  Extrusion E2060 x 80mm |
-|   1 | ```extrusion(E2080, 80)``` |  Extrusion E2080 x 80mm |
-|   1 | ```extrusion(E3030, 80)``` |  Extrusion E3030 x 80mm |
-|   1 | ```extrusion(E3060, 80)``` |  Extrusion E3060 x 80mm |
-|   1 | ```extrusion(E4040, 80)``` |  Extrusion E4040 x 80mm |
-|   1 | ```extrusion(E4080, 80)``` |  Extrusion E4080 x 80mm |
+|   1 | ```extrusion(E2020, 80, false)``` |  Extrusion E2020 x 80mm |
+|   1 | ```extrusion(E2040, 80, false)``` |  Extrusion E2040 x 80mm |
+|   1 | ```extrusion(E2060, 80, false)``` |  Extrusion E2060 x 80mm |
+|   1 | ```extrusion(E2080, 80, false)``` |  Extrusion E2080 x 80mm |
+|   1 | ```extrusion(E3030, 80, false)``` |  Extrusion E3030 x 80mm |
+|   1 | ```extrusion(E3060, 80, false)``` |  Extrusion E3060 x 80mm |
+|   1 | ```extrusion(E4040, 80, false)``` |  Extrusion E4040 x 80mm |
+|   1 | ```extrusion(E4080, 80, false)``` |  Extrusion E4080 x 80mm |
 
 
 <a href="#top">Top</a>
@@ -2425,6 +2474,8 @@ Rocker switch. Also used for neon indicator in the same form factor.
 ## Rod
 Steel rods and studding with chamfered ends.
 
+These items are sysmtrical, so by default the origin is in the centre but it can be changed to the bottom.
+
 
 [vitamins/rod.scad](vitamins/rod.scad) Implementation.
 
@@ -2733,8 +2784,8 @@ SK shaft support brackets
 ### Vitamins
 | Qty | Module call | BOM entry |
 | ---:|:--- |:---|
-|   2 | ```extrusion(E2020, 20)``` |  Extrusion E2020 x 20mm |
-|   2 | ```extrusion(E3030, 20)``` |  Extrusion E3030 x 20mm |
+|   2 | ```extrusion(E2020, 20, false)``` |  Extrusion E2020 x 20mm |
+|   2 | ```extrusion(E3030, 20, false)``` |  Extrusion E3030 x 20mm |
 |   2 | ```sliding_t_nut(M4_hammer_nut)``` |  Nut M4 hammer |
 |   2 | ```sliding_t_nut(M4_sliding_t_nut)``` |  Nut M4 sliding T |
 |   2 | ```sliding_t_nut(M5_sliding_t_nut)``` |  Nut M5 sliding T |
@@ -2836,6 +2887,8 @@ Filament spool models
 ## Springs
 Compression springs. Can be tapered, have open, closed or ground ends. Ground ends will render a lot slower.
 
+By default springs have their origin at the bottom but can be centered.
+
 
 [vitamins/springs.scad](vitamins/springs.scad) Object definitions.
 
@@ -2864,7 +2917,7 @@ Compression springs. Can be tapered, have open, closed or ground ends. Ground en
 ### Modules
 | Module | Description |
 |:--- |:--- |
-| ```comp_spring(type, l = 0)``` | Draw specified spring, l can be set to specify the compressed length. |
+| ```comp_spring(type, l = 0, center = false)``` | Draw specified spring, l can be set to specify the compressed length. |
 
 ![springs](tests/png/springs.png)
 

tests/extrusion_brackets.scad

@@ -0,0 +1,60 @@
+//
+// NopSCADlib Copyright Chris Palmer 2020
+// 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>
+
+include <../vitamins/extrusion_brackets.scad>
+include <../vitamins/extrusions.scad>
+include <../vitamins/washers.scad>
+include <../vitamins/nuts.scad>
+
+module extrusion_brackets() {
+    extrusion_inner_corner_bracket(E20_inner_corner_bracket);
+
+    translate([30, 0])
+        extrusion_inner_corner_bracket(E20_inner_corner_bracket, grub_screws = false);
+
+    translate([60, 0])
+        extrusion_corner_bracket_assembly(E20_corner_bracket);
+
+    eWidth = extrusion_width(E2020);
+
+    translate([0, 60]) {
+        extrusion_inner_corner_bracket(E20_inner_corner_bracket);
+        translate([-eWidth / 2, 0, 0])
+            rotate([-90, 0, 0])
+                extrusion(E2020, 20);
+        translate([-eWidth, -eWidth / 2, 0])
+            rotate([0, 90, 0])
+                extrusion(E2020, 40);
+    }
+
+    translate([60, 60]) {
+        extrusion_corner_bracket_assembly(E20_corner_bracket);
+        translate([-eWidth / 2, 0, 0])
+            rotate([-90, 0, 0])
+                extrusion(E2020, 30);
+        translate([-eWidth, -eWidth / 2, 0])
+            rotate([0, 90, 0])
+                extrusion(E2020, 50);
+    }
+}
+
+if($preview)
+    let($show_threads = true)
+        extrusion_brackets();

vitamins/extrusion.scad

@@ -43,7 +43,7 @@ module extrusion_cross_section(type, cornerHole) {
         fillet = extrusion_fillet(type);
         cornerSize = (width-channelWidth)/2;
         cornerSquare = (width-extrusion_channel_width_internal(type))/2;
-        cornerHoleDiameter =extrusion_corner_hole(type);
+        cornerHoleDiameter = extrusion_corner_hole(type);
 
         translate([-width/2,-width/2]) {
             difference() {
@@ -57,7 +57,7 @@ module extrusion_cross_section(type, cornerHole) {
                     translate([fillet,fillet])
                         square([cornerSquare-fillet,cornerSquare-fillet]);
                 }
-                if(cornerHole)
+                if(cornerHole && cornerHoleDiameter > 0)
                     translate([cornerSquare/2,cornerSquare/2])
                         circle(d=cornerHoleDiameter);
             }
@@ -117,12 +117,12 @@ module extrusion_cross_section(type, cornerHole) {
                 extrusion_center_section(type);
 }
 
-module extrusion(type, length, cornerHole = false) { //! Draw the specified extrusion
+module extrusion(type, length, center = false, cornerHole = false) { //! Draw the specified extrusion
 
-    vitamin(str("extrusion(", type[0], ", ", length, "): Extrusion ", type[0], " x ", length, "mm"));
+    vitamin(str("extrusion(", type[0], ", ", length, ", ", center, "): Extrusion ", type[0], " x ", length, "mm"));
 
     color(grey90)
-        linear_extrude(height = length)
+        linear_extrude(length, center = center)
             extrusion_cross_section(type, cornerHole);
 }
 

vitamins/extrusion_bracket.scad

@@ -0,0 +1,139 @@
+//
+// NopSCADlib Copyright Chris Palmer 2020
+// 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/>.
+//
+
+//! Brackets for joining extrusions at a corner.
+
+include <NopSCADlib/core.scad>
+include <screws.scad>
+include <nuts.scad>
+
+function extrusion_inner_corner_bracket_size(type)             = type[1]; //! Size of inner bracket
+
+module extrusion_inner_corner_bracket(type, grub_screws = true) { //! Inner corner bracket for extrusion
+    vitamin(str("extrusion_inner_corner_bracket(", type[0], ", ", grub_screws, "): Extrusion inner corner bracket ", type[1].z));
+
+    size = extrusion_inner_corner_bracket_size(type);
+    armLength = size.x;
+    bottomTabOffset = 4;
+    topTabOffset = 10;
+    sizeBottom = [armLength - bottomTabOffset, 6, size.z];
+    sizeTop = [armLength - topTabOffset, 6, size.z];
+    tabSizeY1 = 10;
+    tabSizeY2 = 6;
+    tabSizeZ = 3.25;
+    holeRadius = M4_tap_radius;
+
+    translate([-size.z - 0.75, -size.z - 0.75, 0])
+        rotate([-90, 0, 0]) {
+            color("silver") {
+                translate([(armLength + bottomTabOffset) / 2, 0, tabSizeZ])
+                    rotate([0, 180, 0])
+                        extrusionSlidingNut(sizeBottom, tabSizeY1, tabSizeY2, tabSizeZ, holeRadius, (bottomTabOffset - armLength) / 2 + 5);
+                translate([tabSizeZ, 0, (armLength + topTabOffset) / 2])
+                    rotate([0, -90, 0])
+                        extrusionSlidingNut(sizeTop, tabSizeY1, tabSizeY2, tabSizeZ, holeRadius,-(topTabOffset - armLength) / 2 - 5);
+                translate([0, -size.z / 2, 0]) {
+                    cube([bottomTabOffset, size.z, size.z]);
+                    cube([size.z, size.z, topTabOffset]);
+                }
+            }
+            if(grub_screws)
+                not_on_bom() no_explode() {
+                    grubScrewLength = 6;
+                    for(angle = [[0, 0, 0], [0, -90, 180]])
+                        rotate(angle)
+                            translate([armLength - 5, 0, size.z])
+                                screw(M3_grub_screw, grubScrewLength);
+                }
+        }
+}
+
+function extrusion_corner_bracket_size(type)             = type[1]; //! Size of bracket
+function extrusion_corner_bracket_base_thickness(type)   = type[2]; //! Thickness of base of bracket
+function extrusion_corner_bracket_side_thickness(type)   = type[3]; //! Thickness of side of bracket
+function extrusion_corner_bracket_hole_offset(type)      = type[4]; //! Hole offset from corner
+
+module extrusion_corner_bracket(type) { //! Corner bracket for extrusion
+echo(type=type);
+    vitamin(str("extrusion_corner_bracket(", type[0], "): Extrusion corner bracket ", type[1].z));
+
+    eSize = extrusion_corner_bracket_size(type).z;
+    cbSize = extrusion_corner_bracket_size(type).x;
+    baseThickness = extrusion_corner_bracket_base_thickness(type);
+
+    module base() {
+        linear_extrude(baseThickness)
+            difference() {
+                translate([0, -eSize / 2, 0])
+                    square([cbSize, eSize]);
+                hull() {
+                    translate([extrusion_corner_bracket_hole_offset(type) + 1.5, 0, 0])
+                        circle(r = M5_clearance_radius);
+                    translate([extrusion_corner_bracket_hole_offset(type) - 1.5, 0, 0])
+                        circle(r = M5_clearance_radius);
+                }
+            }
+    }
+
+    color("silver") {
+        rotate([90, 0, 90])
+            base();
+        translate([0, baseThickness, 0])
+            rotate([90, 0, 0])
+                base();
+        sideThickness = extrusion_corner_bracket_side_thickness(type);
+        for(z = [-eSize / 2, eSize / 2 - sideThickness]) {
+            translate_z(z) {
+                right_triangle(cbSize, cbSize, sideThickness, center = false);
+                cube([5, cbSize, sideThickness]);
+                cube([cbSize, 5, sideThickness]);
+            }
+        }
+    }
+}
+
+module extrusion_corner_bracket_hole_positions(type) { //! Place children at hole positions
+    for(angle = [ [0, 90, 0], [-90, -90, 0] ])
+        rotate(angle)
+            translate([0, extrusion_corner_bracket_hole_offset(type), extrusion_corner_bracket_base_thickness(type)])
+                children();
+}
+
+module extrusion_corner_bracket_assembly(type, part_thickness = 2, screw_type = M4_cap_screw, nut_type = M4_sliding_t_nut, max_screw_depth = 6) { //! Assembly with fasteners in place
+    extrusion_corner_bracket(type);
+
+    screw_washer_thickness = washer_thickness(screw_washer(screw_type));
+    nut_washer_type = nut_washer(nut_type);
+    nut_washer_thickness = nut_washer_type ? washer_thickness(nut_washer_type) : 0;
+
+    nut_offset = extrusion_corner_bracket_base_thickness(type) + part_thickness;
+    screw_length = max_screw_depth ? screw_shorter_than(extrusion_corner_bracket_base_thickness(type) + screw_washer_thickness + max_screw_depth)
+                                   : screw_longer_than(nut_offset + screw_washer_thickness + nut_washer_thickness + nut_thickness(nut_type));
+
+    extrusion_corner_bracket_hole_positions(type) {
+        screw_and_washer(screw_type, screw_length);
+        translate_z(-nut_offset)
+            vflip()
+                if(nut_washer_type)
+                    nut_and_washer(nut_type);
+                else
+                    rotate(90)
+                        sliding_t_nut(nut_type);
+    }
+}

vitamins/extrusion_brackets.scad

@@ -0,0 +1,29 @@
+//
+// NopSCADlib Copyright Chris Palmer 2020
+// 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/>.
+//
+//
+// Extrusion brackets
+//
+
+E20_inner_corner_bracket  = [ "E20_inner_corner_bracket", [25, 25, 4.5] ];
+
+E20_corner_bracket = [ "E20_corner_bracket", [28, 28, 20], 2, 3, 19.5];
+
+
+use <extrusion_bracket.scad>
+

vitamins/extrusions.scad

@@ -20,10 +20,10 @@
 // Extrusion
 //
 //                   W   H    d1   d2   s  cw   cwi    t  st  f
-E2020  = [ "E2020", 20, 20,  4.2,   0,  8,  6, 12.0,   2,  2, 1 ];
-E2040  = [ "E2040", 20, 40,  4.2,   0,  8,  6, 12.0,   2,  2, 1 ];
-E2060  = [ "E2060", 20, 60,  4.2,   0,  8,  6, 12.0,   2,  2, 1 ];
-E2080  = [ "E2080", 20, 80,  4.2,   0,  8,  6, 12.0,   2,  2, 1 ];
+E2020  = [ "E2020", 20, 20,  4.2,   3,  8,  6, 12.0,   2,  2, 1 ];
+E2040  = [ "E2040", 20, 40,  4.2,   3,  8,  6, 12.0,   2,  2, 1 ];
+E2060  = [ "E2060", 20, 60,  4.2,   3,  8,  6, 12.0,   2,  2, 1 ];
+E2080  = [ "E2080", 20, 80,  4.2,   3,  8,  6, 12.0,   2,  2, 1 ];
 E3030  = [ "E3030", 30, 30,  6.8, 4.2, 12,  8, 16.5,   2,  2, 1 ];
 E3060  = [ "E3060", 30, 60,  6.8, 4.2, 12,  8, 16.5,   2,  2, 1 ];
 E4040  = [ "E4040", 40, 40, 10.5, 6.0, 15, 10, 20.0, 5.5,  3, 1 ];

vitamins/rod.scad

@@ -19,6 +19,8 @@
 
 //
 //! Steel rods and studding with chamfered ends.
+//!
+//! These items are sysmtrical, so by default the origin is in the centre but it can be changed to the bottom.
 //
 include <../core.scad>
 use <../utils/thread.scad>

vitamins/spring.scad

@@ -19,6 +19,8 @@
 
 //
 //! Compression springs. Can be tapered, have open, closed or ground ends. Ground ends will render a lot slower.
+//!
+//! By default springs have their origin at the bottom but can be centered.
 //
 include <../core.scad>
 
@@ -64,7 +66,7 @@ function comp_spring(type, l = 0) = //! Calculate the mesh for spring
         profile = circle_points(wire_d / 2 - eps, $fn = 16)
        ) concat(type, [concat(sweep(path, profile), [l])]);
 
-module comp_spring(type, l = 0) { //! Draw specified spring, l can be set to specify the compressed length.
+module comp_spring(type, l = 0, center = false) { //! Draw specified spring, l can be set to specify the compressed length.
     length = spring_length(type);
     closed = spring_closed(type);
     od = spring_od(type);
@@ -79,14 +81,17 @@ module comp_spring(type, l = 0) { //! Draw specified spring, l can be set to spe
 
     mesh = len(type) > 9 ? spring_mesh(type) : spring_mesh(comp_spring(type, l));
     assert(l == mesh[2], "can't change the length of a pre-generated spring");
-    color(spring_colour(type))
-        if(ground)
-            clip(zmin = 0, zmax = h)
+    len = l ? l : length;
+    translate_z(center ? - len / 2 : 0) {
+        color(spring_colour(type))
+            if(ground)
+                clip(zmin = 0, zmax = h)
+                    polyhedron(mesh[0], mesh[1]);
+            else
                 polyhedron(mesh[0], mesh[1]);
-        else
-            polyhedron(mesh[0], mesh[1]);
 
-    if($children)
-        translate_z(l)
-            children();
+        if($children)
+            translate_z(len)
+                children();
+    }
 }