feat: end cap

.gitignore

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+*.stl

README.md

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+# Parametric Monorail
+
+## Design differences
+
+Injection molding has vastly different requirements to 3d printing.
+Due to this the original rails print absolutely horribly due to the copious amounts of supports needed.
+Surfaces printed on supports just never look good.
+
+Because of that, I decided to instead of having a support part on the bottom, I'd carve out space for
+two stacked 1x2 plates, as well as a special two-high printable brick you can use for compatibility with the
+old support mounts.
+
+_These are 3d printing optimized, compatible rails, not replicas. Replicas print horribly due to support._
+
+## Printing
+
+To be compatible with standard bricks, the following print settings are recommended
+
+- Nozzle: 0.4, this is equivalent to 1 LDU.
+- Layer height: 0.1, though 0.2 will also do. Refrain from using 0.15, since that does not cleanly divides the LDU.
+- Supports: Tree (normal supports may print faster, but lead to way worse results. But ymmv).
+
+My prints were done on a modified SecKit SK-Go2 running Klipper, with 10k acceleration and 150mm/s print speed for a good
+balance of speed and quality. A short rail will take about an hour to print.
+
+### Filament
+
+| Color             | RAL Color  | Pantone | PLA                                                                                                         | ABS |
+| ----------------- | ---------- | ------- | ----------------------------------------------------------------------------------------------------------- | --- | --- |
+| Light Bluish Gray | `RAL 7040` |         | [dasfilament 20,56€/kg](https://www.dasfilament.de/filament-spulen/pla-1-75-mm/8/pla-filament-1-75-mm-grau) |     |
+| Light Gray        | `RAL 7005` |         |                                                                                                             |     |     |
+
+- None of these colors will be an exact match, just the texture of 3d printing it can make a huge difference, but usually fall close enough in the range.
+- The original rails will be in _Light Gray_, not _Light Bluish Gray_, but since I barely own any pre- 2004 color change bricks I chose to match my other bricks instead.
+- Most bricks are injection molded from ABS, however I find PLA to be much more easy and safe to handle.
+  - PLA starts to deform at 60°C, so don't leave it in the sun or in your car.
+  - PLA is brittle. While ABS deforms with force applied to it, PLA will just snap.
+  - ABS is harder to print, an enclosure is a must, and warping can be difficult to handle.
+
+#### Printing Safety
+
+In case you are new to 3D printing:
+
+- Most filaments (including PLA) release toxic gases when _burned_
+- FDM printing can cause fine particle emission
+- ABS when heated to normal printing temperatures can release styrene fumes

track.scad

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+include <lib/BOSL/shapes.scad>;
+include <lib/BOSL/transforms.scad>;
+include <lib/BOSL/constants.scad>;
+
+$LDU=0.4;
+
+$stud=12 * $LDU;
+$studHeight=4 * $LDU;
+
+$tile=20 * $LDU;
+$plate=8 * $LDU;
+$studBrim=$tile - $stud;
+$studSupport=8 * $LDU;
+
+$fillet=$LDU / 2;
+$edgeTolerance=$LDU / 2;
+
+$len = 20;
+
+
+//translate([28.75, -232, -5.75]) rotate([0, 0, 90]) import("straight.stl");
+
+
+$baseHeight = $tile;
+$baseWidth = 4 * $tile;
+
+$teeth = 5;
+$teethTolerance = $LDU;
+$teethRailWidth = 10 * $LDU;
+$teethWidth = $tile / $teeth;
+$teethDepth = 3 * $LDU;
+
+module tooth() {
+  $height = $teethWidth - $teethTolerance;
+  $rail = $teethRailWidth / 2;
+  $topY = $height / 2;
+  $midY = $teethTolerance / 2;
+  $endX = $rail + $teethDepth;
+
+  translate([0, $teethWidth / 2, 0]) linear_extrude($plate) polygon(points=[
+    [$rail, $topY],
+    [$endX, $midY],
+    [$endX, -$midY],
+    [$rail, -$topY],
+    [-$rail, -$topY],
+    [-$endX, -$midY],
+    [-$endX, $midY],
+    [-$rail, $topY]
+  ]);
+}
+
+module brickSlot(w=1, l=1, h=3) {
+  cuboid([$tile * w, $tile * l, $plate * h], align=V_DOWN);
+  mirror_copy([1, 0, 0])
+    mirror_copy([0, 1, 0])
+    translate([$tile / 2, $tile / 2, 0])
+    cyl(d=$fillet, h=$plate * h, align=V_DOWN, $fn=12);
+  difference () {
+    cuboid([$stud+2*$LDU, $stud+2*$LDU, $studHeight], align=V_TOP);
+    mirror_copy([1, -1, 0])
+      mirror_copy([1, 0, 0])
+      translate([$stud / 2, 0, 0])
+      cyl(d=2*$LDU, h=$studHeight, align=V_TOP+V_RIGHT, $fn=12);
+  }
+  mirror_copy([1, 0, 0])
+    mirror_copy([0, 1, 0])
+    translate([$stud/2+$LDU, $stud/2+$LDU, 0])
+    cyl(d=$fillet, h=$studHeight, align=V_TOP, $fn=12);
+}
+
+module endCap() {
+  $width = $baseWidth - $plate * 2;
+  union() {
+    difference() {
+      union() {
+        cuboid([$width, $tile * 2, $tile], edges=EDGE_BOT_FR+EDGE_BOT_RT+EDGE_BOT_LF);
+        mirror_copy([0, 1, 0])
+          translate([0, $tile / 2, 0])
+          cyl(l=$width + $studHeight * 2, d=$stud, orient=ORIENT_X, $fn=24);
+
+        translate([$tile, -$tile, 0]) cuboid([8 * $LDU, $LDU, $tile], align=V_RIGHT+V_FRONT);
+      }
+      mirror_copy([1, 0, 0])
+        mirror_copy([0, 1, 0])
+        translate([$width / 2, $tile / 2, 0])
+        torus(d2=$edgeTolerance, d=$stud, orient=ORIENT_X, $fn=24);
+
+      translate([$plate, $tile / 2, $tile - $LDU]) cube([$LDU, $tile, $LDU]);
+      translate([$width + $plate - $LDU, $tile / 2, $tile - $LDU]) cube([$LDU, $tile, $LDU]);
+  
+      mirror_copy([1, 0, 0])
+        translate([$tile / 2, -$tile / 2, $tile / 2 - $plate])
+        brickSlot();
+
+
+      translate([-$tile, -$tile, 0]) cuboid([8 * $LDU, $LDU, $tile], align=V_LEFT+V_BACK);
+      place_copies([[-$tile, -$tile + $LDU], [$tile + 8 * $LDU, -$tile, 0]])
+        mirror_copy([1, 0, 0], cp=[-4 * $LDU, 0, 0])
+        cyl(d=$fillet, h=$tile, $fn=12);
+    }
+
+    translate([0, $teethTolerance / 2, $tile / 2]) cuboid([$teethRailWidth, $tile * 2 - $teethTolerance, $plate], align=V_TOP);
+    translate([0, -$tile, $tile / 2]) group() {
+      for (i = [0:(2 * $teeth - 1)]) {
+        translate([0, i * $teethWidth, 0]) tooth();
+      }
+    };
+  }
+}
+
+
+endCap();