(Some what OT:) Marching tetrahedra

I am looking for an (Understandable) tutorial on marching tetrahedra (the variation of the marching cubes). I LOVE the marching cubes, BUT someone at GE had to go and patent the thing &*#$($)**%&$(#, any who, does anyone know a good source to learn about the tetrahedra version (something understandable though? cause all the sources i have found so far have been about CRT scans and stuff, which dosnt go into HOW to do it). Please and thank you.

Marching cubes is a very specific optimization that walks the volume to find an iso surface quickly. It can actually miss data on some datasets.

Just do brute force cube thresholding and you won’t be implementing marching cubes. I haven’t seen what claims are in the GE patent, but it’s a safe bet that there’s some patent out there you’ll infringe on no matter what you implement.

Paul Bourke has some marching tetrahedra code (look into marchingsource.cpp)