Changed some teardrop holes to teardrop plus.

staircasing and added a plus option to tearslot(), etc.

Added horiholes.scad to depict staircase holes.

printed/door_hinge.scad

@@ -74,7 +74,7 @@ module door_hinge(door_thickness) {                         //! Generates STL fo
                             square([1, thickness + door_thickness]);
                     }
                     translate([dia / 2, thickness + door_thickness / 2])
-                        teardrop(r = screw_clearance_radius(pin_screw), h = 0);
+                        teardrop_plus(r = screw_clearance_radius(pin_screw), h = 0);
                 }
         linear_extrude(thickness)
             difference() {
@@ -127,7 +127,7 @@ module door_hinge_stat_stl() { //! Generates the STL for the stationary part
                             square([dia, 1], center = true);
                     }
                     translate([0, dia / 2 + stat_clearance])
-                        teardrop(r = screw_clearance_radius(pin_screw), h = 0);
+                        teardrop_plus(r = screw_clearance_radius(pin_screw), h = 0);
                }
     }
 }

readme.md

@@ -24,18 +24,18 @@ See [usage](docs/usage.md) for requirements, installation instructions and a usa
 <tr><td> <a href = "#Belts">Belts</a> </td><td> <a href = "#LED_meters">LED_meters</a> </td><td> <a href = "#Rod">Rod</a> </td><td> <a href = "#Carriers">Carriers</a> </td><td> <a href = "#Fillet">Fillet</a> </td><td> <a href = "#Polyholes">Polyholes</a> </td></tr>
 <tr><td> <a href = "#Blowers">Blowers</a> </td><td> <a href = "#LEDs">LEDs</a> </td><td> <a href = "#SCS_bearing_blocks">SCS_bearing_blocks</a> </td><td> <a href = "#Corner_block">Corner_block</a> </td><td> <a href = "#Gears">Gears</a> </td><td> <a href = "#Rounded_rectangle">Rounded_rectangle</a> </td></tr>
 <tr><td> <a href = "#Bulldogs">Bulldogs</a> </td><td> <a href = "#Leadnuts">Leadnuts</a> </td><td> <a href = "#SK_brackets">SK_brackets</a> </td><td> <a href = "#Door_hinge">Door_hinge</a> </td><td> <a href = "#Hanging_hole">Hanging_hole</a> </td><td> <a href = "#Sphere">Sphere</a> </td></tr>
-<tr><td> <a href = "#Buttons">Buttons</a> </td><td> <a href = "#Light_strips">Light_strips</a> </td><td> <a href = "#SMDs">SMDs</a> </td><td> <a href = "#Door_latch">Door_latch</a> </td><td> <a href = "#Layout">Layout</a> </td><td> <a href = "#Teardrops">Teardrops</a> </td></tr>
-<tr><td> <a href = "#Cable_strips">Cable_strips</a> </td><td> <a href = "#Linear_bearings">Linear_bearings</a> </td><td> <a href = "#SSRs">SSRs</a> </td><td> <a href = "#Fan_guard">Fan_guard</a> </td><td> <a href = "#Maths">Maths</a> </td><td></td></tr>
-<tr><td> <a href = "#Cameras">Cameras</a> </td><td> <a href = "#Mains_sockets">Mains_sockets</a> </td><td> <a href = "#Screws">Screws</a> </td><td> <a href = "#Fixing_block">Fixing_block</a> </td><td> <a href = "#Offset">Offset</a> </td><td></td></tr>
-<tr><td> <a href = "#Circlips">Circlips</a> </td><td> <a href = "#Microswitches">Microswitches</a> </td><td> <a href = "#Sealing_strip">Sealing_strip</a> </td><td> <a href = "#Flat_hinge">Flat_hinge</a> </td><td> <a href = "#Quadrant">Quadrant</a> </td><td></td></tr>
-<tr><td> <a href = "#Components">Components</a> </td><td> <a href = "#Microview">Microview</a> </td><td> <a href = "#Sheets">Sheets</a> </td><td> <a href = "#Foot">Foot</a> </td><td> <a href = "#Round">Round</a> </td><td></td></tr>
-<tr><td> <a href = "#DIP">DIP</a> </td><td> <a href = "#Modules">Modules</a> </td><td> <a href = "#Spades">Spades</a> </td><td> <a href = "#Handle">Handle</a> </td><td> <a href = "#Rounded_cylinder">Rounded_cylinder</a> </td><td></td></tr>
-<tr><td> <a href = "#D_connectors">D_connectors</a> </td><td> <a href = "#Nuts">Nuts</a> </td><td> <a href = "#Spools">Spools</a> </td><td> <a href = "#PCB_mount">PCB_mount</a> </td><td> <a href = "#Rounded_polygon">Rounded_polygon</a> </td><td></td></tr>
-<tr><td> <a href = "#Displays">Displays</a> </td><td> <a href = "#O_ring">O_ring</a> </td><td> <a href = "#Springs">Springs</a> </td><td> <a href = "#PSU_shroud">PSU_shroud</a> </td><td> <a href = "#Sector">Sector</a> </td><td></td></tr>
-<tr><td> <a href = "#Extrusion_brackets">Extrusion_brackets</a> </td><td> <a href = "#Opengrab">Opengrab</a> </td><td> <a href = "#Stepper_motors">Stepper_motors</a> </td><td> <a href = "#Printed_box">Printed_box</a> </td><td> <a href = "#Sweep">Sweep</a> </td><td></td></tr>
-<tr><td> <a href = "#Extrusions">Extrusions</a> </td><td> <a href = "#PCB">PCB</a> </td><td> <a href = "#Swiss_clips">Swiss_clips</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 = "#Fans">Fans</a> </td><td> <a href = "#PCBs">PCBs</a> </td><td> <a href = "#Toggles">Toggles</a> </td><td> <a href = "#SSR_shroud">SSR_shroud</a> </td><td> <a href = "#Tube">Tube</a> </td><td></td></tr>
-<tr><td> <a href = "#Fuseholder">Fuseholder</a> </td><td> <a href = "#PSUs">PSUs</a> </td><td> <a href = "#Transformers">Transformers</a> </td><td> <a href = "#Screw_knob">Screw_knob</a> </td><td></td><td></td></tr>
+<tr><td> <a href = "#Buttons">Buttons</a> </td><td> <a href = "#Light_strips">Light_strips</a> </td><td> <a href = "#SMDs">SMDs</a> </td><td> <a href = "#Door_latch">Door_latch</a> </td><td> <a href = "#Horiholes">Horiholes</a> </td><td> <a href = "#Teardrops">Teardrops</a> </td></tr>
+<tr><td> <a href = "#Cable_strips">Cable_strips</a> </td><td> <a href = "#Linear_bearings">Linear_bearings</a> </td><td> <a href = "#SSRs">SSRs</a> </td><td> <a href = "#Fan_guard">Fan_guard</a> </td><td> <a href = "#Layout">Layout</a> </td><td></td></tr>
+<tr><td> <a href = "#Cameras">Cameras</a> </td><td> <a href = "#Mains_sockets">Mains_sockets</a> </td><td> <a href = "#Screws">Screws</a> </td><td> <a href = "#Fixing_block">Fixing_block</a> </td><td> <a href = "#Maths">Maths</a> </td><td></td></tr>
+<tr><td> <a href = "#Circlips">Circlips</a> </td><td> <a href = "#Microswitches">Microswitches</a> </td><td> <a href = "#Sealing_strip">Sealing_strip</a> </td><td> <a href = "#Flat_hinge">Flat_hinge</a> </td><td> <a href = "#Offset">Offset</a> </td><td></td></tr>
+<tr><td> <a href = "#Components">Components</a> </td><td> <a href = "#Microview">Microview</a> </td><td> <a href = "#Sheets">Sheets</a> </td><td> <a href = "#Foot">Foot</a> </td><td> <a href = "#Quadrant">Quadrant</a> </td><td></td></tr>
+<tr><td> <a href = "#DIP">DIP</a> </td><td> <a href = "#Modules">Modules</a> </td><td> <a href = "#Spades">Spades</a> </td><td> <a href = "#Handle">Handle</a> </td><td> <a href = "#Round">Round</a> </td><td></td></tr>
+<tr><td> <a href = "#D_connectors">D_connectors</a> </td><td> <a href = "#Nuts">Nuts</a> </td><td> <a href = "#Spools">Spools</a> </td><td> <a href = "#PCB_mount">PCB_mount</a> </td><td> <a href = "#Rounded_cylinder">Rounded_cylinder</a> </td><td></td></tr>
+<tr><td> <a href = "#Displays">Displays</a> </td><td> <a href = "#O_ring">O_ring</a> </td><td> <a href = "#Springs">Springs</a> </td><td> <a href = "#PSU_shroud">PSU_shroud</a> </td><td> <a href = "#Rounded_polygon">Rounded_polygon</a> </td><td></td></tr>
+<tr><td> <a href = "#Extrusion_brackets">Extrusion_brackets</a> </td><td> <a href = "#Opengrab">Opengrab</a> </td><td> <a href = "#Stepper_motors">Stepper_motors</a> </td><td> <a href = "#Printed_box">Printed_box</a> </td><td> <a href = "#Sector">Sector</a> </td><td></td></tr>
+<tr><td> <a href = "#Extrusions">Extrusions</a> </td><td> <a href = "#PCB">PCB</a> </td><td> <a href = "#Swiss_clips">Swiss_clips</a> </td><td> <a href = "#Ribbon_clamp">Ribbon_clamp</a> </td><td> <a href = "#Sweep">Sweep</a> </td><td></td></tr>
+<tr><td> <a href = "#Fans">Fans</a> </td><td> <a href = "#PCBs">PCBs</a> </td><td> <a href = "#Toggles">Toggles</a> </td><td> <a href = "#SSR_shroud">SSR_shroud</a> </td><td> <a href = "#Thread">Thread</a> </td><td></td></tr>
+<tr><td> <a href = "#Fuseholder">Fuseholder</a> </td><td> <a href = "#PSUs">PSUs</a> </td><td> <a href = "#Transformers">Transformers</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 = "#Geared_steppers">Geared_steppers</a> </td><td> <a href = "#Panel_meters">Panel_meters</a> </td><td> <a href = "#Tubings">Tubings</a> </td><td> <a href = "#Socket_box">Socket_box</a> </td><td></td><td></td></tr>
 <tr><td> <a href = "#Green_terminals">Green_terminals</a> </td><td> <a href = "#Pillars">Pillars</a> </td><td> <a href = "#Variacs">Variacs</a> </td><td> <a href = "#Strap_handle">Strap_handle</a> </td><td></td><td></td></tr>
 <tr><td> <a href = "#Hot_ends">Hot_ends</a> </td><td> <a href = "#Pin_headers">Pin_headers</a> </td><td> <a href = "#Veroboard">Veroboard</a> </td><td></td><td></td><td></td></tr>
@@ -5287,6 +5287,31 @@ Method to print holes in mid air. See <https://hydraraptor.blogspot.com/2014/03/
 ![hanging_hole](tests/png/hanging_hole.png)
 
 
+<a href="#top">Top</a>
+
+---
+<a name="Horiholes"></a>
+## 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>
+
+
+[utils/horiholes.scad](utils/horiholes.scad) Implementation.
+
+[tests/horiholes.scad](tests/horiholes.scad) Code for this example.
+
+### Functions
+| Function | Description |
+|:--- |:--- |
+| ```teardrop_plus_x(r, y, h)``` | Calculate the ordinate of a compensated teardrop given y and layer height. |
+
+### Modules
+| Module | Description |
+|:--- |:--- |
+| ```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)
+
+
 <a href="#top">Top</a>
 
 ---
@@ -5859,6 +5884,9 @@ This ensures `hull` and `minkowski` results have the correct dimensions when sph
 For making horizontal holes that don't need support material.
 Small holes can get away without it, but they print better with truncated teardrops.
 
+Using teardrop_plus() or setting the plus option on other modules will elongate the teardrop vertically by the layer height, so when sliced the staircase tips
+do not intrude into the circle. See <https://hydraraptor.blogspot.com/2020/07/horiholes-2.html>
+
 
 [utils/core/teardrops.scad](utils/core/teardrops.scad) Implementation.
 
@@ -5867,12 +5895,12 @@ Small holes can get away without it, but they print better with truncated teardr
 ### Modules
 | Module | Description |
 |:--- |:--- |
-| ```semi_teardrop(h, r, d = undef, center = true, chamfer = 0)``` | A semi teardrop in the positive Y domain |
-| ```teardrop(h, r, center = true, truncate = true, chamfer = 0)``` | For making horizontal holes that don't need support material, set ```truncate = false``` to make traditional RepRap teardrops that don't even need bridging |
+| ```semi_teardrop(h, r, d = undef, center = true, chamfer = 0, plus = false)``` | A semi teardrop in the positive Y domain |
+| ```teardrop(h, r, center = true, truncate = true, chamfer = 0, plus = false)``` | For making horizontal holes that don't need support material, set ```truncate = false``` to make traditional RepRap teardrops that don't even need bridging |
 | ```teardrop_chamfer(h, center, chamfer)``` | Helper module for adding chamfer to a teardrop |
-| ```teardrop_plus(h, r, center = true, truncate = true, chamfer = 0)``` | Slightly bigger teardrop to allow for the 3D printing staircase effect |
-| ```tearslot(h, r, w, center = true, chamfer = 0)``` | A horizontal slot that doesn't need support material |
-| ```vertical_tearslot(h, r, l, center = true, chamfer = 0)``` | A vertical slot that doesn't need support material |
+| ```teardrop_plus(h, r, center = true, truncate = true, chamfer = 0)``` | Slightly elongated teardrop to allow for the 3D printing staircase effect |
+| ```tearslot(h, r, w, center = true, chamfer = 0, plus = false)``` | A horizontal slot that doesn't need support material |
+| ```vertical_tearslot(h, r, l, center = true, chamfer = 0, plus = false)``` | A vertical slot that doesn't need support material |
 
 ![teardrops](tests/png/teardrops.png)
 

tests/horiholes.scad

@@ -0,0 +1,90 @@
+//
+// 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/>.
+//
+$layer_height = 0.25;
+include <../utils/core/core.scad>
+use <../utils/horiholes.scad>
+
+show_disc = true;
+use_horihole = true;
+thickness = 6;
+length = 60;
+height = 20;
+overlap_x = 15;
+overlap_y = 10;
+
+module hole_positions() {
+    x0 = (length - 40) / 2;
+    for($i = [0 : 4], $z = 5 + $i * layer_height / 5, $r = 3)
+        translate([x0 + $i * 10, $z])
+            children();
+
+    for($i = [0 : 4], $z = 15 + $i * layer_height / 5, $r = 0.5 + $i / 2)
+        translate([x0 + $i * 10, $z])
+            children();
+}
+
+module horiholes_stl(t = thickness) {
+    rotate([90, 0, 0])
+        difference() {
+            linear_extrude(t, center = true) {
+                difference() {
+                    square([length, height]);
+
+                    hole_positions()
+                        if(use_horihole)
+                            horihole($r, $z);
+                        else
+                            teardrop_plus(h = 0, r = $r);
+                }
+            }
+        }
+    if(t == thickness)
+        translate([length / 2, 0])
+            rounded_rectangle([length + 2 * overlap_x, thickness + 2 * overlap_y, 2], 5);
+}
+
+module horiholes() {
+    stl_colour(pp1_colour)
+        rotate([-90, 0, 0])
+            horiholes_stl(eps);
+
+    if(show_disc)
+        hole_positions()
+            color(silver)
+                cylinder(r = $r, h = eps, center = true, $fn = 360);
+
+    hole_positions()
+        color("red")
+            linear_extrude(2 * eps, center = true)
+                intersection() {
+                    difference() {
+                        square(8, center = true);
+
+                        horihole($r, $z);
+                    }
+
+                    circle($r, $fn = 360);
+                }
+}
+
+if($preview)
+    rotate(is_undef($bom) ? 0 : [70, 0, 315])
+        horiholes();
+else
+    horiholes_stl();

tests/printed_box.scad

@@ -67,7 +67,7 @@ module box1_external_additions() {
 
 module box1_holes() {
     box1_feet_positions()
-        teardrop(r = screw_pilot_hole(foot_screw(foot)), h = 10, center = true);
+        teardrop_plus(r = screw_pilot_hole(foot_screw(foot)), h = 10, center = true);
 }
 
 

tests/teardrops.scad

@@ -41,7 +41,10 @@ module teardrops() {
 
                         translate([20, 10])
                             semi_teardrop(h = 0, r = 3);
-                    }
+
+                        translate([20, 20])
+                            teardrop(h = 0, r = 3, truncate = false, plus = true);
+                   }
                 }
                 translate([40, 0, 1.5]) {
                     h = 3 + eps;
@@ -61,6 +64,9 @@ module teardrops() {
 
                     translate([20, 10])
                         semi_teardrop(h = h, r = 3, chamfer = chamfer);
+
+                    translate([20, 20])
+                        teardrop(h = h, r = 3, truncate = false, plus = false, chamfer = chamfer);
                 }
             }
 }

utils/core/teardrops.scad

@@ -20,17 +20,32 @@
 //
 //! For making horizontal holes that don't need support material.
 //! Small holes can get away without it, but they print better with truncated teardrops.
+//!
+//! Using teardrop_plus() or setting the plus option on other modules will elongate the teardrop vertically by the layer height, so when sliced the staircase tips
+//! do not intrude into the circle. See <https://hydraraptor.blogspot.com/2020/07/horiholes-2.html>
 //
-module teardrop(h, r, center = true, truncate = true, chamfer = 0) { //! For making horizontal holes that don't need support material, set ```truncate = false``` to make traditional RepRap teardrops that don't even need bridging
+module teardrop(h, r, center = true, truncate = true, chamfer = 0, plus = false) { //! For making horizontal holes that don't need support material, set ```truncate = false``` to make traditional RepRap teardrops that don't even need bridging
     module teardrop_2d(r, truncate) {
-        hull() {
-            circle4n(r);
-            if(truncate)
-                translate([0, r / 2])
-                    square([2 * r * (sqrt(2) - 1), r], center = true);
-            else
-                polygon([[0, 0], [eps, 0], [0, r * sqrt(2)]]);
-        }
+        er = layer_height / 2 - eps;    // Extrustion edge radius
+        R = plus ? r + er : r;          // Corrected radius
+        offset = plus ? -er : 0;        // Offset inwards
+        hull()
+            for(side = [0 : 1])
+                mirror([side, 0, 0])
+                    intersection() {
+                        hull()
+                        translate([offset, 0]) {
+                            circle4n(R);
+
+                            if(truncate)
+                                translate([0, R / 2])
+                                    square([2 * R * (sqrt(2) - 1), R], center = true);
+                            else
+                                polygon([[0, 0], [eps, 0], [0, R * sqrt(2)]]);
+                        }
+                        translate([0, -2 * R])
+                            square([R, 4 * R]);
+                    }
     }
 
     render(convexity = 5)
@@ -40,23 +55,23 @@ module teardrop(h, r, center = true, truncate = true, chamfer = 0) { //! For mak
     teardrop_chamfer(h, center, chamfer) {
         linear_extrude(eps, center = true)
             teardrop_2d(r + chamfer / 2, truncate);
+
         translate_z(-chamfer / 2)
             linear_extrude(eps, center = true)
                 teardrop_2d(r, truncate);
     }
 }
 
-module semi_teardrop(h, r, d = undef, center = true, chamfer = 0) { //! A semi teardrop in the positive Y domain
-    module semi_teardrop_2d(r, d) {
+module semi_teardrop(h, r, d = undef, center = true, chamfer = 0, plus = false) { //! A semi teardrop in the positive Y domain
+    module semi_teardrop_2d(r, d)
         intersection() {
             R = is_undef(d) ? r : d / 2;
-            teardrop(r = R, h = 0);
+            teardrop(r = R, h = 0, plus = plus);
 
             sq = R + 1;
             translate([-sq, 0])
                 square([2 * sq, sq]);
         }
-    }
 
     render(convexity = 5)
         extrude_if(h, center)
@@ -65,22 +80,21 @@ module semi_teardrop(h, r, d = undef, center = true, chamfer = 0) { //! A semi t
     teardrop_chamfer(h, center, chamfer) {
         linear_extrude(eps, center = true)
             semi_teardrop_2d(r + chamfer / 2, d);
+
         translate_z(-chamfer / 2)
             linear_extrude(eps, center = true)
                 semi_teardrop_2d(r, d);
     }
 }
 
-module teardrop_plus(h, r, center = true, truncate = true, chamfer = 0) //! Slightly bigger teardrop to allow for the 3D printing staircase effect
-    teardrop(h, r + layer_height / 4, center, truncate, chamfer);
+module teardrop_plus(h, r, center = true, truncate = true, chamfer = 0) //! Slightly elongated teardrop to allow for the 3D printing staircase effect
+    teardrop(h, r, center, truncate, chamfer, plus = true);
 
-module tearslot(h, r, w, center = true, chamfer = 0) { //! A horizontal slot that doesn't need support material
-    module tearslot_2d(r, w) {
-        hull() {
-            translate([-w / 2, 0]) teardrop(r = r, h = 0);
-            translate([w / 2, 0]) teardrop(r = r, h = 0);
-        }
-    }
+module tearslot(h, r, w, center = true, chamfer = 0, plus = false) { //! A horizontal slot that doesn't need support material
+    module tearslot_2d(r, w)
+        hull()
+            for(x = [-1, 1])
+                translate([x * w / 2, 0]) teardrop(r = r, h = 0, plus = plus);
 
     extrude_if(h, center)
         tearslot_2d(r, w);
@@ -88,19 +102,19 @@ module tearslot(h, r, w, center = true, chamfer = 0) { //! A horizontal slot tha
     teardrop_chamfer(h, center, chamfer) {
         linear_extrude(eps, center = true)
             tearslot_2d(r + chamfer / 2, w);
+
         translate_z(-chamfer / 2)
             linear_extrude(eps, center = true)
                 tearslot_2d(r, w);
     }
 }
 
-module vertical_tearslot(h, r, l, center = true, chamfer = 0) { //! A vertical slot that doesn't need support material
-    module vertical_tearslot_2d(r, l) {
-        hull() {
-            translate([0,  l / 2]) teardrop(0, r, true);
-            translate([0, -l / 2]) circle4n(r);
-        }
-    }
+module vertical_tearslot(h, r, l, center = true, chamfer = 0, plus = false) { //! A vertical slot that doesn't need support material
+    module vertical_tearslot_2d(r, l)
+        hull()
+            for(y = [-1, 1])
+                translate([0,  y * l / 2])
+                    teardrop(0, r, true, plus = plus);
 
     extrude_if(h, center)
         vertical_tearslot_2d(r, l);
@@ -108,6 +122,7 @@ module vertical_tearslot(h, r, l, center = true, chamfer = 0) { //! A vertical s
     teardrop_chamfer(h, center, chamfer) {
         linear_extrude(eps, center = true)
             vertical_tearslot_2d(r + chamfer / 2, l);
+
         translate_z(-chamfer / 2)
             linear_extrude(eps, center = true)
                 vertical_tearslot_2d(r, l);
@@ -123,4 +138,3 @@ module teardrop_chamfer(h, center, chamfer) { //! Helper module for adding chamf
                         hull()
                             children();
 }
-

utils/horiholes.scad

@@ -0,0 +1,55 @@
+//
+// 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/>.
+//
+
+//
+//! Utilities for depicting the staircase slicing of horizontal holes made with [`teardrop_plus()`](#teardrops), see <https://hydraraptor.blogspot.com/2020/07/horiholes-2.html>
+//
+include <../utils/core/core.scad>
+
+function teardrop_plus_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
+    )
+    max(0,
+        y < hpot / sqrt(2) ? x - fr :
+        y < hpot           ? hpot * sqrt(2) - y - fr :
+        0);
+
+module horihole(r, z, h = 0, center = true) { //! For making horizontal holes 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_plus_x(r, y, layer_height);
+                if(x > 0)
+                    translate([0, y])
+                        difference() {
+                            square([2 * x + layer_height, layer_height], center = true);
+
+                            for(end = [-1, 1])
+                                translate([end * (x + layer_height / 2), 0])
+                                    circle(d = layer_height, $fn = 32);
+                        }
+             }
+}

vitamins/wire.scad

@@ -50,7 +50,7 @@ module mouse_hole(cable, h = 100, teardrop = false) { //! A mouse hole to allow
     r = wire_hole_radius(cable);
 
         if(teardrop)
-            vertical_tearslot(r = r, l = 2 * r, h = h);
+            vertical_tearslot(r = r, l = 2 * r, h = h, plus = true);
         else
             rotate(90)
                 slot(r, 2 * r, h = h);