Hyperbolic tilings library

thingiverse

I added an Instructable on how to use this library to make cookies: https://www.instructables.com/id/Hyperbolic-Cookies/. This OpenSCAD library allows for customizable tilings of the hyperbolic plane (in the Poincaré disk model) by triangle groups. A triangle group is defined by a triplet (p,q,r) where 1/p+1/q+1/r < 1, and invoked as `triangle_group(p,q,r)`. The number 0 represents the special value ∞. Any infinite numbers must precede finite numbers (i.e. `triangle_group(0,2,3)` is legal, while `triangle_group(2,0,3)` is not — this would be the same group anyway). Tessellation data is computed from the triangle group with `tgroup_tessellation_data(group, depth)`, where the `depth` parameter is the number of consecutive reflections from the center tile. Modules building the 3D object use this tessellation data; a few modules are provided as examples, such as `tessellation_simple` and `tessellation_cookie` (which builds a cookie cutter for hyperbolic cookies). It should be quite simple to build your own modules starting from these. Note that the same tiling (same triangle group) can give quite different objects depending on how you mark edges. You can e.g. construct a tiling or its dual this way, for example either 7 triangles or 3 heptagons meeting at each vertex. Warning: Oh, and given the recursive, exponential complexity of these tilings, generating STLs is **long** (about 15 minutes on my laptop at depth 3, and a crash at depth 4). I strongly advise you to use a very small `depth` parameter for tweaking (as in, 0 or 1), and only when you have a design you like to go up to depth 3 or 4. Since this is basically a stress test for CGAL, it might also decide to crash your computer or teleport you to some unpleasant place.