My grand plan was to finish Alien::OpenCASCADE and then build a companion module for Math::3Space that makes it easy to specify triangle meshes and uses OpenCASCADE to perform solid modeling operations on them (union/difference/intersection) in the style of OpenSCAD, but procedural with objects. Then, combine those two with OpenGL::Sandbox to view it. (I considered using OpenSCAD's underlying C libraries, but read that they were quite a bit less performant than OpenCASCADE)

I haven't finished reading your PDL version of Math::3Space, but my first impression so far is that I'd like to make my modules PDL-aware so that they can read and write to ndarrays (like created by your trigrid3d or loaded from STL), and then for parallel processing just make new modules in the PDL namespace that perform these same operations the PDL-way.