Reuleaux Triangle for FDM

This is a derivative of both thing:1088 and thing:1082, with inspiration from the improved snap from thing:5322. However the pattern was totally redrawn from basic principles to make it fully parametric, rather than relying on the original dxf outlines.

The point of this design is to take full advantages of the abilities of a 3d printer, rather than just converting a laser cut design into a 3d part with difficult overhangs. The triangle should end up fully trapped inside the case.

Note that from a top view, it may appear the triangle and case overlap, but from a per-layer perspective, they are separated by the tolerance, and do not actually touch.

UPDATE: Modern machines are able to print with tighter tolerances than what was available when I designed this. So I have added reuleaux_assy-05.stl which has tolerance=0.5 mm instead of 1mm. Printed perfectly with no cleaning necessary in my Ender 3.