When doing cardiac simulations, you’d think heart-shaped models would be ideal. However, for many basic science projects, a slab-shaped model with various regions of various shapes is more desirable. This allows isolation of geometry to answer a specific question. Historically people have used all sorts of tools to do this. Recently I’ve actually been using OpenSCAD to mock things up and make flat images, which I then massage through ImageJ and GIMP until I get something I can feed into the voxel-based mesher Tarantula.
This is really suboptimal, though. There must be some sort of constructive geometry modeler out there like OpenSCAD that will do proper volume meshes. OpenSCAD is really for surface meshes, but it’s so very easy to make the shapes I want in it. To that end I’ve been searching for FOSS CSG software, and I’m now trying the first one I found that has promise — BRL-CAD. I’ll post more as I try it out.
EDIT: So far so good the MGED editor in BRL-CAD seems to be WAY more powerful than OpenSCAD, much as I love OpenSCAD. I will post some designs as I get the hang of it.