Added functions for generating twisted cable paths and calculating its radius.

Top row of cable bundles reversed to match a twisted cable.

CHANGELOG.md

@@ -3,6 +3,13 @@
 This changelog is generated by `changelog.py` using manually added semantic version tags to classify commits as breaking changes, additions or fixes.
 
 
+#### [v20.1.1](https://github.com/nophead/NopSCADlib/releases/tag/v20.1.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v20.1.0...v20.1.1 "diff with v20.1.0")
+*   2022-02-25 [`943deed`](https://github.com/nophead/NopSCADlib/commit/943deededfe2b258f23ca64001ae7c010ed626bc "show commit") [C.P.](# "Chris Palmer") Updated the readme.
+
+*   2022-02-24 [`c0d9067`](https://github.com/nophead/NopSCADlib/commit/c0d9067b740fc5ea4a41e696c88613a284685118 "show commit") [M.B.](# "Martin Budden") Fixed typos.
+
+*   2022-02-25 [`a30aff9`](https://github.com/nophead/NopSCADlib/commit/a30aff9613f51092bbad7052bfe1194a61557efc "show commit") [C.P.](# "Chris Palmer") Fixed missing brackets for sheets with chamfered corners.
+
 ### [v20.1.0](https://github.com/nophead/NopSCADlib/releases/tag/v20.1.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v20.0.1...v20.1.0 "diff with v20.0.1")
 *   2022-02-23 [`f173284`](https://github.com/nophead/NopSCADlib/commit/f173284709acdbd32de21f0d27cb3ab10b42eb2a "show commit") [C.P.](# "Chris Palmer") Can now inhibit exploded lines for issue [#220](https://github.com/nophead/NopSCADlib/issues/220 "show issue").
 

readme.md

@@ -4382,7 +4382,7 @@ If a washer is given a child, usually a screw or a nut, then it is placed on its
 ---
 <a name="Wire"></a>
 ## Wire
-Just a BOM entry at the moment and cable bundle size functions for holes, plus cable ties.
+Utilities for adding wires to the BOM and optionally drawing them and cable bundle size functions for holes, plus cable ties.
 
 [vitamins/wire.scad](vitamins/wire.scad) Implementation.
 
@@ -4391,21 +4391,25 @@ Just a BOM entry at the moment and cable bundle size functions for holes, plus c
 ### Functions
 | Function | Description |
 |:--- |:--- |
-| `cable(wires, size, colours, ribbon = false)` | Cable constructor |
-| `cable_bundle(cable)` | Arrangement of a bundle in a flat cable clip |
+| `cable(wires, size, colours, ribbon = false, tlen = 25)` | Cable constructor |
+| `cable_bundle(cable)` | Dimensions of the bounding rectangle of a bundle of wires in a flat cable clip |
 | `cable_bundle_positions(cable)` | Positions of wires in a bundle to go through a cable strip |
 | `cable_height(cable)` | Height in flat clip |
 | `cable_is_ribbon(cable)` | Is a ribbon cable? |
 | `cable_radius(cable)` | Radius of a bundle of wires, see <http://mathworld.wolfram.com/CirclePacking.html>. |
+| `cable_tlen(cable)` | Twisted cable twist length |
+| `cable_twisted_radius(cable)` | Approximate radius of a cable when twisted |
 | `cable_width(cable)` | Width in flat clip |
 | `cable_wire_colours(cable)` | Individual wire colours |
 | `cable_wire_size(cable)` | Size of each wire in a bundle |
 | `cable_wires(cable)` | Number of wires in a bundle |
+| `twisted_cable(cable, path, irot = 0, frot = 0)` | Return the paths for a twisted cable, `irot` is the initial rotation and frot the final rotation |
 | `wire_hole_radius(cable)` | Radius of a hole to accept a bundle of wires, rounded up to standard metric drill size |
 
 ### Modules
 | Module | Description |
 |:--- |:--- |
+| `cable(cable, paths)` | Draw a cable, given a list of paths |
 | `cable_tie(cable_r, thickness)` | A ziptie threaded around cable radius `cable_r` and through a panel with specified `thickness`. |
 | `cable_tie_holes(cable_r, h = 100)` | Holes to thread a ziptie through a panel to make a cable tie. |
 | `mouse_hole(cable, h = 100, teardrop = false)` | A mouse hole to allow a panel to go over a wire bundle. |
@@ -4417,13 +4421,13 @@ Just a BOM entry at the moment and cable bundle size functions for holes, plus c
 ### Vitamins
 | Qty | Module call | BOM entry |
 | ---:|:--- |:---|
-|   1 |  |  Wire black 7/0.2mm strands, length 90mm |
-|   1 |  |  Wire blue 7/0.2mm strands, length 90mm |
-|   1 |  |  Wire brown 7/0.2mm strands, length 90mm |
-|   1 |  |  Wire green 7/0.2mm strands, length 90mm |
-|   1 |  |  Wire orange 7/0.2mm strands, length 90mm |
-|   1 |  |  Wire red 7/0.2mm strands, length 90mm |
-|   1 |  |  Wire yellow 7/0.2mm strands, length 90mm |
+|   1 |  |  Wire black 7/0.2mm strands, length 60mm |
+|   1 |  |  Wire blue 7/0.2mm strands, length 60mm |
+|   1 |  |  Wire brown 7/0.2mm strands, length 60mm |
+|   1 |  |  Wire green 7/0.2mm strands, length 60mm |
+|   1 |  |  Wire orange 7/0.2mm strands, length 60mm |
+|   1 |  |  Wire red 7/0.2mm strands, length 60mm |
+|   1 |  |  Wire yellow 7/0.2mm strands, length 60mm |
 |   1 | `ziptie(small_ziptie)` |  Ziptie 2.5mm x 100mm min length |
 
 

tests/wire.scad

@@ -17,18 +17,25 @@
 // If not, see <https://www.gnu.org/licenses/>.
 //
 include <../utils/core/core.scad>
+use <../utils/sweep.scad>
+use <../utils/bezier.scad>
 
 use <../vitamins/wire.scad>
 
-bundle = [7, 1.4];
+twist_len = 25; // [5 : 50]
+wires = 7; // [1 : 7]
+irot = -60; // [-90 : 0]
 
+/* [Hidden] */
+wire_d = 1.4;
+bundle = cable(wires, wire_d);
 bundle_r = cable_radius(bundle);
 
 thickness = 2;
 w = 60;
 d = 20;
-h = 40;
-wire_l = 90;
+h = 10;
+wire_l = 60;
 mouse_y = 10;
 cable_pitch = 7;
 
@@ -49,6 +56,7 @@ module wires() {
                     translate([bundle_r - d / 2, 0]) {
                         colour = ["black", "brown", "red", "orange", "yellow", "blue", "purple"][i];
                         wire(colour, 7, wire_l);
+
                         color(colour)
                             cylinder(d = d, h = wire_l, center = true);
                    }
@@ -66,7 +74,7 @@ module wires() {
                         mouse_hole(bundle, 0, true);
 
                     for(i = [1 : 6])
-                        let(cable = [i, 1.4], bundle = cable_bundle(cable))
+                        let(cable = cable(i, wire_d), bundle = cable_bundle(cable))
                             translate([mouse_y + cable_pitch * i - bundle.x / 2, -eps])
                                 square([bundle.x, bundle.y]);
                 }
@@ -81,18 +89,28 @@ module wires() {
                         cable_tie_holes(bundle_r, 0);
                 }
     }
+
     translate([-15, mouse_y])
         cable_tie(bundle_r, thickness);
 
-    for(i = [1 : 6]) let(cable = [i, 1.4])
-        translate([0, mouse_y + cable_pitch * i])
-            let(positions = cable_bundle_positions(cable))
-                for(i = [0 : len(positions) - 1])
-                    let(p = positions[i])
-                        translate([0, p.x, p.y])
-                            rotate([0, 90, 0])
-                                color([grey(10), "blue", "red", "orange", "yellow", "green"][i])
-                                    cylinder(d = cable_wire_size(cable), h = 60, center = true);
+    for(i = [1 : 6]) let(cable = cable(i, wire_d, [grey(10), "blue", "red", "orange", "yellow", "green"], tlen = twist_len))
+        translate([0, mouse_y + cable_pitch * i]) {
+            tr = cable_twisted_radius(cable);
+            bend_r = 5;
+            x = -d + thickness - bend_r;
+            path = [
+                        [-5, 0, tr],
+                        [x,  0, tr],
+                bend_r, [x,  0, -25]
+            ];
+            rpath = rounded_path(path);
+            tpaths = twisted_cable(cable, rpath, irot = irot, frot = -irot);
+            positions = cable_bundle_positions(cable);
+
+            ends = [for(p = positions) [[30, p.x, p.y], [0, p.x, p.y]]];
+            paths = [for(i = [0 : len(tpaths) - 1]) bezier_join(ends[i], tpaths[i], 1.3, 3)];
+            cable(cable, paths, $fn = 32);
+        }
 }
 
 if($preview)

tests/zipties.scad

@@ -16,14 +16,23 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+wire_r = 5; // [1 : 20]
+t = 0; // [0 : 3]
+
 include <../utils/core/core.scad>
 use <../utils/layout.scad>
 
 include <../vitamins/zipties.scad>
 
 module zipties()
-    layout([for(z = zipties) 9], 10)
-        ziptie(zipties[$i], 5);
+    layout([for(z = zipties) 9], 2 * wire_r) {
+        ziptie(zipties[$i], wire_r, t);
+
+        if(t)
+            color(grey(20))
+                cylinder(r = wire_r, h = 10, center = true);
+
+    }
 
 if($preview)
     zipties();

utils/sweep.scad

@@ -241,8 +241,7 @@ function segmented_path(path, min_segment) = [  //! Add points to a path to enfo
 
 function spiral_paths(path, n, r, twists, start_angle) = let( //! Create a new paths which sprial around the given path. Use for making twisted cables
         segment = twists ? path_length(path) / twists / r2sides(2 * r) : inf,
-        transforms = sweep_transforms(segmented_path(path, segment), twist = 360 * twists),
-        initial = [r, 0, 0, 1] * rotate(start_angle)
+        transforms = sweep_transforms(segmented_path(path, segment), twist = 360 * twists)
     ) [for(i = [0 : n - 1]) let(initial = [r, 0, 0, 1] * rotate(start_angle + i * 360 / n)) [for(t = transforms) initial * t]];
 
 function rounded_path_vertices(path) = [path[0], for(i = [1 : 2 : len(path) - 1]) path[i]]; //! Show the unrounded version of a rounded_path for debug

vitamins/wire.scad

@@ -18,9 +18,11 @@
 //
 
 //
-//! Just a BOM entry at the moment and cable bundle size functions for holes, plus cable ties.
+//! Utilities for adding wires to the BOM and optionally drawing them and cable bundle size functions for holes, plus cable ties.
 //
 include <../utils/core/core.scad>
+use <../utils/sweep.scad>
+use <../utils/maths.scad>
 include <zipties.scad>
 
 module wire(colour, strands, length, strand = 0.2)   //! Add stranded wire to the BOM
@@ -35,15 +37,16 @@ module ribbon_cable(ways, length)                   //! Add ribbon cable to the
 function cable_wires(cable)     = cable[0]; //! Number of wires in a bundle
 function cable_wire_size(cable) = cable[1]; //! Size of each wire in a bundle
 function cable_is_ribbon(cable) = len(cable) > 2 && cable[2]; //! Is a ribbon cable?
-function cable_wire_colours(cable) = assert(len(cable[3]) == cable_wires(cable)) cable[3]; //! Individual wire colours
-function cable(wires, size, colours, ribbon = false) = [wires, size, ribbon, colours]; //! Cable constructor
+function cable_wire_colours(cable) = assert(len(cable[3]) >= cable_wires(cable)) cable[3]; //! Individual wire colours
+function cable_tlen(cable)      = cable[4]; //! Twisted cable twist length
+function cable(wires, size, colours, ribbon = false, tlen = 25) = [wires, size, ribbon, colours, tlen]; //! Cable constructor
 
 // numbers from http://mathworld.wolfram.com/CirclePacking.html
 function cable_radius(cable) = [0, 1, 2, 2.15, 2.41, 2.7, 3, 3, 3.3][cable_wires(cable)] * cable_wire_size(cable) / 2; //! Radius of a bundle of wires, see <http://mathworld.wolfram.com/CirclePacking.html>.
 
 function wire_hole_radius(cable) = ceil(4 * cable_radius(cable) + 1) / 4; //! Radius of a hole to accept a bundle of wires, rounded up to standard metric drill size
 
-function cable_bundle(cable) = //! Arrangement of a bundle in a flat cable clip
+function cable_bundle(cable) = //! Dimensions of the bounding rectangle of a bundle of wires in a flat cable clip
     (cable_is_ribbon(cable) ? [cable_wires(cable), 1] :
     [[0,0], [1,1], [2,1], [2, 1 + sin(60)], [2,2], [3, 1 + sin(60)], [3,2]][cable_wires(cable)]) * cable_wire_size(cable);
 
@@ -53,12 +56,42 @@ function cable_bundle_positions(cable) = let( //! Positions of wires in a bundle
         top = wires - bottom
     )
     [for(i = [0 : 1 : bottom - 1]) [i - (bottom - 1) / 2, 0.5],
-     for(i = [0 : 1 : top - 1])    [i - (top - 1) / 2, top == bottom ? 1.5 : 0.5 + sin(60)]
+     for(i = [top - 1 : -1 : 0])   [i - (top - 1) / 2, top == bottom ? 1.5 : 0.5 + sin(60)]
     ] * cable_wire_size(cable);
 
 function cable_width(cable)  = cable_bundle(cable).x; //! Width in flat clip
 function cable_height(cable) = cable_bundle(cable).y; //! Height in flat clip
 
+function cable_twisted_radius(cable) = let( //! Approximate radius of a cable when twisted
+        tlen = cable_tlen(cable),               // Twist length
+        a = cable_wire_size(cable) / 2,         // Ellipse minor axis
+        R = cable_radius(cable) - a,            // Radius of wire centres when not twisted
+        angle = atan2(tlen, 2 * PI * R),        // Slope angle of the spiral
+        b = a / sin(angle),                     // Ellipse major axis
+        grad = tan(180 / cable_wires(cable)),   // Gradient at contact point between elipses
+        x = a^2 / sqrt(a^2 + (b / grad)^2),     // Contact point of the ellipse tangent
+        y = b * sqrt(1 - x^2 / a^2)
+    ) R ? x + y / grad + a : a;                 // Where the tangent meets the X axis plus radius
+
+function twisted_cable(cable, path, irot = 0, frot = 0) = let(      //! Return the paths for a twisted cable, `irot` is the initial rotation and frot the final rotation
+        tlen = cable_tlen(cable),               // Twist length
+        r = cable_wire_size(cable) / 2,
+        pitch = cable_twisted_radius(cable) - r,
+        wires = cable_wires(cable),
+        bottom = wires > 4 ? 3 : 2,
+        irot = irot + 90 - 180 * (bottom - 1) / wires
+    )
+    spiral_paths(path, wires, pitch, round(path_length(path) / tlen) - frot / 360, irot);
+
+module cable(cable, paths) {                    //! Draw a cable, given a list of paths
+    wires = cable_wires(cable);
+    assert(len(paths) == wires);
+    r = cable_wire_size(cable) / 2;
+    for(i = [0 : wires - 1])
+        color(cable_wire_colours(cable)[i])
+            sweep(paths[i], circle_points(r), convexity = 5);
+}
+
 module mouse_hole(cable, h = 100, teardrop = false) { //! A mouse hole to allow a panel to go over a wire bundle.
     r = wire_hole_radius(cable);
 

vitamins/ziptie.scad

@@ -33,17 +33,16 @@ function ziptie_tail(type)      = type[5]; //! The length without teeth
 module ziptie(type, r = 5, t = 0) //! Draw specified ziptie wrapped around radius `r` and optionally through panel thickness `t`
 {
     latch = ziptie_latch(type);
-    lx = latch.x / 2;
     zt = ziptie_thickness(type);
-    cr = zt;                        // sharp corner radius
+    lx = min(latch.x / 2, r + zt / 2);
+    right_bulge = (r > lx - zt / 2) || !t;
+    cr = zt / 2;                        // sharp corner radius
     z = r + t - cr;
     x = r - cr;
-    inside_corners  = t ? [ [0, 0, r],      [-x, z, cr],      [x, z, cr]      ] : [];
     outside_corners = t ? [ [0, 0, r + zt], [-x, z, cr + zt], [x, z, cr + zt] ] : [];
     x1 = lx - zt / 2;
     x2 = x1 + x1 * zt / r;
-    inside_path  = concat([ [0, 0, r],      [x1, -r,      eps] ], inside_corners);
-    outside_path = concat([ [0, 0, r + zt], [x2, -r - zt, eps] ], outside_corners);
+    outside_path = concat([ if(right_bulge) [0, 0, r + zt], [x2, -r - zt, eps] ], outside_corners);
 
     tangents = rounded_polygon_tangents(outside_path);
     length = ceil(rounded_polygon_length(outside_path, tangents) + ziptie_tail(type) + latch.z + 1);
@@ -56,7 +55,9 @@ module ziptie(type, r = 5, t = 0) //! Draw specified ziptie wrapped around radiu
         linear_extrude(width, center = true)
             difference() {
                 rounded_polygon(outside_path, tangents);
-                rounded_polygon(inside_path);
+
+                offset(-zt)
+                    rounded_polygon(outside_path, tangents);
              }
 
         translate([lx, -r])