Added NEMA_connection_pos().

Changed motor wire colours and tweaked wire position and size,

CHANGELOG.md

@@ -3,6 +3,29 @@
 This changelog is generated by `changelog.py` using manually added semantic version tags to classify commits as breaking changes, additions or fixes.
 
 
+### [v20.7.0](https://github.com/nophead/NopSCADlib/releases/tag/v20.7.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v20.6.1...v20.7.0 "diff with v20.6.1")
+*   2022-06-21 [`28c36a4`](https://github.com/nophead/NopSCADlib/commit/28c36a4e966cceccbbdc330cf9a6fdeaa0283889 "show commit") [C.P.](# "Chris Palmer") `rounded_polygon()` now copes with the degenerate case when tangents intersect to form a sharp corner with no arc.
+Added an `offset()` function with some limitations.
+
+#### [v20.6.1](https://github.com/nophead/NopSCADlib/releases/tag/v20.6.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v20.6.0...v20.6.1 "diff with v20.6.0")
+*   2022-06-21 [`6a9af0a`](https://github.com/nophead/NopSCADlib/commit/6a9af0af8aef68978b8be248810d07c85150341b "show commit") [C.P.](# "Chris Palmer") Updates images
+
+*   2022-06-21 [`a6a0808`](https://github.com/nophead/NopSCADlib/commit/a6a08088d986dbcbc4d01c06e0475176ec8bc76f "show commit") [M.B.](# "Martin Budden") Fixed dimensions of E1515 extrusion.
+
+*   2022-06-21 [`bcf9fb3`](https://github.com/nophead/NopSCADlib/commit/bcf9fb38dfabaf93508a380b85b12e3b23f28cf8 "show commit") [M.B.](# "Martin Budden") Fixed typos.
+
+*   2022-06-21 [`06443a5`](https://github.com/nophead/NopSCADlib/commit/06443a558b407292a1e73f60c24cc90ec618d511 "show commit") [M.B.](# "Martin Budden") Standardised setting of imgsize in scripts.
+
+### [v20.6.0](https://github.com/nophead/NopSCADlib/releases/tag/v20.6.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v20.5.1...v20.6.0 "diff with v20.5.1")
+*   2022-06-14 [`18f3d43`](https://github.com/nophead/NopSCADlib/commit/18f3d43780d7e083fc3b21290db2049fb4364a46 "show commit") [C.P.](# "Chris Palmer") Added convexity parameter to `clip()`.
+
+#### [v20.5.1](https://github.com/nophead/NopSCADlib/releases/tag/v20.5.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v20.5.0...v20.5.1 "diff with v20.5.0")
+*   2022-06-14 [`eda88cc`](https://github.com/nophead/NopSCADlib/commit/eda88cc8d75eb4c0cb59b368b4e2ad3db2115834 "show commit") [C.P.](# "Chris Palmer") Fixed `vero()` constructor documentation.
+Fixed missing space in veroboard vitamin description.
+
+*   2022-06-14 [`630268d`](https://github.com/nophead/NopSCADlib/commit/630268d71a0b478c28b6bde2a7c3ff9074c7a8fb "show commit") [C.P.](# "Chris Palmer") Changed `screw_knob()` facets to be suitable for 3D printing.
+Fixed `knob_height()` so it can take a screw as a type.
+
 ### [v20.5.0](https://github.com/nophead/NopSCADlib/releases/tag/v20.5.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v20.4.0...v20.5.0 "diff with v20.4.0")
 *   2022-05-31 [`cc5654d`](https://github.com/nophead/NopSCADlib/commit/cc5654d7d756287f5311e35104003f38a4a94475 "show commit") [C.](# "Chris") Added `usb_miniA()`.
 

readme.md

@@ -3887,6 +3887,7 @@ NEMA stepper motor model.
 | Function | Description |
 |:--- |:--- |
 | `NEMA_big_hole(type)` | Clearance hole for the big boss |
+| `NEMA_connection_pos(type, jst_connector = false)` | Position of the wires or the connector |
 | `NEMA_holes(type)` | Screw positions for for loop |
 
 ### Modules
@@ -6608,6 +6609,8 @@ Because the tangents need to be calculated to find the length these can be calcu
 | Function | Description |
 |:--- |:--- |
 | `circle_tangent(p1, p2)` | Compute the clockwise tangent between two circles represented as [x,y,r] |
+| `line_intersection(l0, l1)` | Return the point where two 2D lines intersect or undef if they don't. |
+| `offset(points, offset)` | Offset a 2D polygon, breaks for concave shapes and negative offsets if the offset is more than half the smallest feature size. |
 | `rounded_polygon(points, _tangents = undef)` | Return the rounded polygon from the point list, can pass the tangent list to save it being calculated |
 | `rounded_polygon_arcs(points, tangents)` | Compute the arcs at the points, for each point [angle, rotate_angle, length] |
 | `rounded_polygon_length(points, tangents)` | Calculate the length given the point list and the list of tangents computed by `rounded_polygon_tangents` |

tests/stepper_motors.scad

@@ -16,18 +16,28 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+show_connection_pos = false;
+
+/* [Hidden] */
 include <../core.scad>
 include <../vitamins/stepper_motors.scad>
 
 use <../utils/layout.scad>
 
+has_connector = [NEMA17_27, NEMA17_40, NEMA17_40L280, NEMA8_30, NEMA8_30BH];
+
 module stepper_motors()
     layout([for(s = stepper_motors) NEMA_width(s)], 5, no_offset = false) let(m = stepper_motors[$i]) {
-        rotate(180)
-            NEMA(m, 0, in([NEMA17_27, NEMA17_40, NEMA17_40L280, NEMA8_30, NEMA8_30BH], m));
+        rotate(180) {
+            NEMA(m, 0, in(has_connector, m) ? true : show_connection_pos ? undef : false);
 
-        translate_z(4)
-            NEMA_screws(m, M3_pan_screw, n = $i - 2, earth = $i > 6 ? undef : $i - 3);
+            if(show_connection_pos)
+                translate(NEMA_connection_pos(m, in(has_connector, m)))
+                    sphere();
+
+            translate_z(4)
+                NEMA_screws(m, M3_pan_screw, n = $i - 2, earth = $i > 6 ? undef : $i - 3);
+        }
     }
 
 if($preview)

utils/rounded_polygon.scad

@@ -33,7 +33,7 @@ function circle_tangent(p1, p2) = //! Compute the clockwise tangent between two
         dx = p2.x - p1.x,
         dy = p2.y - p1.y,
         d = sqrt(dx * dx + dy * dy),
-        theta = atan2(dy, dx) + acos((r1 - r2) / d),
+        theta = assert(d, str("points conicident ", p1)) atan2(dy, dx) + acos((r1 - r2) / d),
         v = [cos(theta), sin(theta)]
     )[ p1 + r1 * v, p2 + r2 * v ];
 
@@ -72,24 +72,52 @@ function rounded_polygon_length(points, tangents) = //! Calculate the length giv
         arcs = rounded_polygon_arcs(points, tangents)
     ) sumv( map( concat(tangents, arcs), function(e) e[2] ) );
 
+function line_intersection(l0, l1) = //! Return the point where two 2D lines intersect or undef if they don't.
+    assert(Len(l0) == 2 && Len(l1) == 2, "Two 2D vectors expected")
+    let(
+        p0 = l0[0], p1 = l0[1], p2 = l1[0], p3 = l1[1],
+        v1 = p1 - p0,
+        v2 = p3 - p2,
+        v3 = p0 - p2,
+        det = v1.x * v2.y - v2.x * v1.y,
+        s = det ? (-v1.y * v3.x + v1.x * v3.y) / det : inf,
+        t = det ? ( v2.x * v3.y - v2.y * v3.x) / det : inf
+    ) s >= 0 && s <= 1 && t >= 0 && t <= 1 ? p0 + t * v1 : undef;
+
 function rounded_polygon(points, _tangents = undef) = //! Return the rounded polygon from the point list, can pass the tangent list to save it being calculated
     let(
         len = len(points),
         tangents = _tangents ? _tangents : rounded_polygon_tangents(points),
         arcs = rounded_polygon_arcs(points, tangents)
-    ) [for(i = [0 : len - 1], last = (i - 1 + len) % len, R = points[i][2]) each [
-        vec2(tangents[last][1]),                        // End of last tangent
-        if(R)                                               // If rounded
-            let(r = abs(R),                                     // Get radius
-                n = r2sides4n(r),                               // Decide number of vertices
-                step = 360 / n,                                 // Angular step
-                arc = arcs[i],                                  // Get corner arc details
-                start = ceil(arc[1] / step + eps),              // Starting index
-                end = floor((arc[0] + arc[1]) / step - eps),    // Ending index
-                c = vec2(points[i])                             // Centre of arc
-            ) for(j = R > 0 ? [end : -1 : start] : [start : 1 : end], a = j * step) c + r * [cos(a), sin(a)], // Points on the arc
-        vec2(tangents[i][0])]                           // Start of next tangent
+    ) [for(i = [0 : len - 1], last = (i - 1 + len) % len)
+        let(
+            t0 = vec2(tangents[last]),
+            t1 = vec2(tangents[i]),
+            p = line_intersection(t0, t1),                              // Do the tangents cross?
+            R = points[i][2]
+        )
+        if(!is_undef(p))                                                // Tangents intersect, so just add the intersection point
+            p
+        else
+            each [                                                      // Else link the two tangent ends with an arc
+                t0[1],                                                  // End of last tangent
+                if(R)                                                   // If rounded
+                    let(r = abs(R),                                     // Get radius
+                        n = r2sides4n(r),                               // Decide number of vertices
+                        step = 360 / n,                                 // Angular step
+                        arc = arcs[i],                                  // Get corner arc details
+                        start = ceil(arc[1] / step + eps),              // Starting index
+                        end = floor((arc[0] + arc[1]) / step - eps),    // Ending index
+                        c = vec2(points[i])                             // Centre of arc
+                    ) for(j = R > 0 ? [end : -1 : start] : [start : 1 : end], a = j * step)
+                        c + r * [cos(a), sin(a)],                       // Points on the arc
+                if(R)
+                    t1[0],                                              // Start of next tangent
+            ]
        ];
 
+function offset(points, offset) =                                       //! Offset a 2D polygon, breaks for concave shapes and negative offsets if the offset is more than half the smallest feature size.
+    rounded_polygon([for(p = points) [p.x, p.y, offset]]);
+
 module rounded_polygon(points, _tangents = undef) //! Draw the rounded polygon from the point list, can pass the tangent list to save it being calculated
     polygon(rounded_polygon(points, _tangents), convexity = len(points));

vitamins/stepper_motor.scad

@@ -51,6 +51,18 @@ stepper_body_colour = grey(20);
 stepper_cap_colour  = grey(50);
 stepper_machined_colour = grey(90);
 
+function NEMA_connection_pos(type, jst_connector = false) = let( //! Position of the wires or the connector
+        side = NEMA_width(type),
+        length = NEMA_length(type),
+        cap = NEMA_cap_heights(type)[1],
+        hdr = NEMA_end_connector(type) ? jst_zh_header : jst_ph_header,
+        socket_size = hdr_box_size(hdr),
+        end_conn_inset = socket_size.y - 2
+    )
+    jst_connector ? NEMA_end_connector(type) ? [0, side / 2 + hdr_y_offset(hdr) + socket_size.y / 2 - end_conn_inset, -length]
+                                             : [0, side / 2 + socket_size.z,  hdr_y_offset(hdr) - socket_size.y / 2 - length + cap]
+                  : [0, side / 2, -length + cap / 2];
+
 module NEMA_outline(type) //! 2D outline
     intersection() {
         side = NEMA_width(type);
@@ -185,14 +197,14 @@ module NEMA(type, shaft_angle = 0, jst_connector = false) { //! Draw specified N
                 not_on_bom()
                     leadscrew(shaft_rad * 2, shaft.x + length + shaft2, shaft.y, shaft.z, center = false);
 
-    if(!jst_connector)
+    if(jst_connector == false)
         translate([0, side / 2, -length + cap / 2])
             rotate([90, 0, 0])
                 for(i = [0 : 3])
                     rotate(225 + i * 90)
-                        color(["red", "blue","green","black"][i])
-                            translate([1, 0, 0])
-                                cylinder(r = 1.5 / 2, h = 12, center = true);
+                        color(["red", "green", "black", "blue"][i])
+                            translate([1.48 / sqrt(2), 0, 0])
+                                cylinder(d = 1.48, h = 12, center = true);
 }
 
 module NEMA_screw_positions(type, n = 4) { //! Positions children at the screw holes