Alan Cox pointed me long ago to implicitcad, because it implements fillets and chamfers by rounding intersections and unions. I kept meaning to play with it…
Tonight my wife asked me whether I could 3D print a set of catenary
arch blocks as math teaching aids. To my surprise, I couldn’t find
a set to print. I saw that ImplicitCAD (unlike OpenSCAD) implements
cosh() and figured it was the right tool for the job. Sadly,
I find no way to define arbitrary polyhedra in ImplicitCAD.
grep polyhedron in the source code comes up empty. There’s no
hull or loft or minkowski sum, either. So I guess back to OpenSCAD
and do it the hard way.