Test image pixel differences due to switch to winter computer

core.scad

@@ -18,7 +18,7 @@
 //
 
 //
-// Include this file to use the miniumum library plus screws, nuts and washers
+// Include this file to use the minimum library plus screws, nuts and washers
 //
 include <utils/core/core.scad>
 //

global_defs.scad

@@ -33,7 +33,7 @@ $exploded       = is_undef($explode)         ? 0      : $explode;         // 1 f
 layer_height    = is_undef($layer_height)    ? 0.25   : $layer_height;    // layer heigth when printing
 extrusion_width = is_undef($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    : $cnc_bit_r;       // miniumum tool radius when milling 2D objects
+cnc_bit_r       = is_undef($cnc_bit_r)       ? 1.2    : $cnc_bit_r;       // minimum tool radius when milling 2D objects
 pp1_colour      = is_undef($pp1_colour)      ? [0, 146/255, 0] : $pp1_colour; // printed part colour 1, RepRap logo colour
 pp2_colour      = is_undef($pp2_colour)      ? "red"  : $pp2_colour;      // printed part colour 2
 pp3_colour      = is_undef($pp3_colour)      ? "blue" : $pp3_colour;      // printed part colour 3

readme.md

@@ -403,7 +403,7 @@ PCB mounted buttons. Can optionally have a coloured cap
 ## Cable_strips
 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 miniumum 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, epecially
 near the extreme positions, where the model needs to be accurate.
 
 When the sides are constrained then a circular model is more accurate.
@@ -5387,6 +5387,8 @@ Method to print holes in mid air. See <https://hydraraptor.blogspot.com/2014/03/
 ## Horiholes
 Utilities for depicting the staircase slicing of horizontal holes made with [`teardrop_plus()`](#teardrops), see <https://hydraraptor.blogspot.com/2020/07/horiholes-2.html>
 
+```horicylinder()``` makes cylinders that fit inside a round hole. Layers that are less than 2 filaments wide and layers that need more than a 45 degree overhang are omitted.
+
 
 [utils/horiholes.scad](utils/horiholes.scad) Implementation.
 
@@ -5395,11 +5397,13 @@ Utilities for depicting the staircase slicing of horizontal holes made with [`te
 ### Functions
 | Function | Description |
 |:--- |:--- |
+| ```teardrop_minus_x(r, y, h)``` | Calculate the ordinate of a compensated teardrop given y and layer height. |
 | ```teardrop_plus_x(r, y, h)``` | Calculate the ordinate of a compensated teardrop given y and layer height. |
 
 ### Modules
 | Module | Description |
 |:--- |:--- |
+| ```horicylinder(r, z, h = 0, center = true)``` | For making horizontal cylinders that don't need support material and are correct dimensions |
 | ```horihole(r, z, h = 0, center = true)``` | For making horizontal holes that don't need support material and are correct dimensions |
 
 ![horiholes](tests/png/horiholes.png)

tests/horiholes.scad

@@ -69,9 +69,13 @@ module horiholes() {
             color(silver)
                 cylinder(r = $r, h = eps, center = true, $fn = 360);
 
+    hole_positions()
+        color("blue")
+            horicylinder(r = $r, z = $z, h = 2 * eps, center = true, $fn = 360);
+
     hole_positions()
         color("red")
-            linear_extrude(2 * eps, center = true)
+            linear_extrude(3 * eps, center = true)
                 intersection() {
                     difference() {
                         square(8, center = true);

utils/core/core.scad

@@ -18,7 +18,7 @@
 //
 
 //
-// Include this file to use the miniumum library
+// Include this file to use the minimum library
 //
 include <../../global_defs.scad>
 //

utils/horiholes.scad

@@ -19,6 +19,8 @@
 
 //
 //! Utilities for depicting the staircase slicing of horizontal holes made with [`teardrop_plus()`](#teardrops), see <https://hydraraptor.blogspot.com/2020/07/horiholes-2.html>
+//!
+//! ```horicylinder()``` makes cylinders that fit inside a round hole. Layers that are less than 2 filaments wide and layers that need more than a 45 degree overhang are omitted.
 //
 include <../utils/core/core.scad>
 
@@ -53,3 +55,29 @@ module horihole(r, z, h = 0, center = true) { //! For making horizontal holes th
                         }
              }
 }
+
+function teardrop_minus_x(r, y, h) = //! Calculate the ordinate of a compensated teardrop given y and layer height.
+    let(fr = h / 2,
+        hpot = r - fr,
+        x2 = sqr(hpot) - sqr(y),
+        x = x2 > 0 ? sqrt(x2) : 0,
+        X = y >= -hpot / sqrt(2) ? x + fr : 0
+    )
+    X >= extrusion_width ? X : 0;
+
+module horicylinder(r, z, h = 0, center = true) { //! For making horizontal cylinders that don't need support material and are correct dimensions
+    bot_layer = floor((z - r) / layer_height);
+    top_layer = ceil((z + r) / layer_height);
+    render(convexity = 5)
+        extrude_if(h, center)
+            for(i = [bot_layer : top_layer]) {
+                Z = i * layer_height;
+                y = Z - z + layer_height / 2;
+                x = teardrop_minus_x(r, y, layer_height);
+                if(x >= extrusion_width)
+                    hull()
+                        for(end = [-1, 1])
+                            translate([end * (x - layer_height / 2), y])
+                                circle(d = layer_height, $fn = 32);
+             }
+}

utils/sweep.scad

@@ -34,14 +34,22 @@ function transpose3(m) = [ [m[0].x, m[1].x, m[2].x],
                            [m[0].y, m[1].y, m[2].y],
                            [m[0].z, m[1].z, m[2].z] ];
 //
+// Find the first non-colinear point
+//
+tiny = 0.00001;
+function find_curve(tangents, i = 1) =
+    i >= len(tangents) - 1 || norm(cross(tangents[0], tangents[i] - tangents[0])) > tiny ? i
+                                                                                         : find_curve(tangents, i + 1);
+//
 // Frenet-Serret frame
 //
 function fs_frame(tangents) =
     let(tangent = tangents[0],
-        normal = tangents[1] - tangents[0],
+        i = find_curve(tangents),
+        normal = tangents[i] - tangents[0],
         binormal = cross(tangent, normal),
         z = unit(tangent),
-        x = assert(norm(binormal) > 0.00001, "first three points are colinear") unit(binormal),
+        x = assert(norm(binormal) > tiny, "all points are colinear") unit(binormal),
         y = unit(cross(z, x))
        ) [[x.x, y.x, z.x],
           [x.y, y.y, z.y],
@@ -70,7 +78,6 @@ function orientate(p, r) =
          [x.y, y.y, z.y],
          [x.z, y.z, z.z],
          [p.x, p.y, p.z]];
-
 //
 // Rotate around z
 //

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 miniumum 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, epecially
 //! near the extreme positions, where the model needs to be accurate.
 //!
 //! When the sides are constrained then a circular model is more accurate.