Added earth_rot parameter to NEMA_screws().

CHANGELOG.md

@@ -3,6 +3,14 @@
 This changelog is generated by `changelog.py` using manually added semantic version tags to classify commits as breaking changes, additions or fixes.
 
 
+### [v19.4.0](https://github.com/nophead/NopSCADlib/releases/tag/v19.4.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v19.3.0...v19.4.0 "diff with v19.3.0")
+*   2022-01-29 [`f33a067`](https://github.com/nophead/NopSCADlib/commit/f33a0675f5b9f6a5ebe1c4b9755e894d1e2b7994 "show commit") [C.P.](# "Chris Palmer") Updated images and readme.
+
+*   2022-01-29 [`5223415`](https://github.com/nophead/NopSCADlib/commit/52234154294011d4cc312f9ff98716f484d20a41 "show commit") [C.P.](# "Chris Palmer") Ball bearing test now two rows.
+
+*   2022-01-28 [`f87f3f5`](https://github.com/nophead/NopSCADlib/commit/f87f3f51ee778ef7ca30319d1d6ff3f4013e8258 "show commit") [M.B.](# "Martin Budden") Added support for flanged bearings.
+Also added some new cartridge bearings.
+
 ### [v19.3.0](https://github.com/nophead/NopSCADlib/releases/tag/v19.3.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v19.2.0...v19.3.0 "diff with v19.2.0")
 *   2022-01-29 [`1ee80f4`](https://github.com/nophead/NopSCADlib/commit/1ee80f4a908ff9939d06186f3b22f54f726fc4d2 "show commit") [C.P.](# "Chris Palmer") Ribbon clamps can now be made to hold multiple ribbons.
 

readme.md

@@ -3876,7 +3876,7 @@ NEMA stepper motor model.
 | `NEMA(type, shaft_angle = 0, jst_connector = false)` | Draw specified NEMA stepper motor |
 | `NEMA_outline(type)` | 2D outline |
 | `NEMA_screw_positions(type, n = 4)` | Positions children at the screw holes |
-| `NEMA_screws(type, screw, n = 4, screw_length = 8, earth = undef)` | Place screws and optional earth tag |
+| `NEMA_screws(type, screw, n = 4, screw_length = 8, earth = undef, earth_rot = undef)` | Place screws and optional earth tag |
 
 ![stepper_motors](tests/png/stepper_motors.png)
 

utils/maths.scad

@@ -103,11 +103,11 @@ function reverse(v) = let(n = len(v) - 1) n < 0 ? [] : [for(i = [0 : n]) v[n - i
 
 function angle_between(v1, v2) = acos(v1 * v2 / (norm(v1) * norm(v2))); //! Return the angle between two vectors
 
-// https://www.gregslabaugh.net/publications/euler.pdf
+// http://eecs.qmul.ac.uk/~gslabaugh/publications/euler.pdf
 function euler(R) = let(ay = asin(-R[2][0]), cy = cos(ay)) //! Convert a rotation matrix to a Euler rotation vector.
     cy ? [ atan2(R[2][1] / cy, R[2][2] / cy), ay, atan2(R[1][0] / cy, R[0][0] / cy) ]
-       : R[2][0] < 0 ? [atan2( R[0][1],  R[0][2]),  180, 0]
-                     : [atan2(-R[0][1], -R[0][2]), -180, 0];
+       : R[2][0] < 0 ? [atan2( R[0][1],  R[0][2]),  90, 0]
+                     : [atan2(-R[0][1], -R[0][2]), -90, 0];
 
 module position_children(list, t) //! Position children if they are on the Z = 0 plane when transformed by t
     for(p = list)

vitamins/stepper_motor.scad

@@ -205,12 +205,12 @@ module NEMA_screw_positions(type, n = 4) { //! Positions children at the screw h
                     children();
 }
 
-module NEMA_screws(type, screw, n = 4, screw_length = 8, earth = undef) //! Place screws and optional earth tag
+module NEMA_screws(type, screw, n = 4, screw_length = 8, earth = undef, earth_rot = undef) //! Place screws and optional earth tag
     NEMA_screw_positions(type, n)
         if($i != earth)
             screw_and_washer(screw, screw_length, true);
         else
-            rotate($i > 1 ? 180 : 0)
+            rotate(is_undef(earth_rot) ? $i > 1 ? 180 : 0 : earth_rot)
                 ring_terminal(M3_ringterm)
                     star_washer(screw_washer(screw))
                         screw(screw, screw_length);