I haven't done any kind of 3D design in many years, but I was thinking last week that it would be fun to get back to it. And while I was looking at software available for Linux, I found Blender.
Blender has been around for quite some time but it seems that now it's features are up to par with some of the most popular 3D packages like 3DS Max or Alias.
Apart from the 3D design tools Blender has one very cool feature, a Python API! I will post another note after I have the chance to try it out.