Truevision is a 3D modeler for Gnome.  It is still in development, so not
really stable and quite not usable yet.

Features:

   - Create some objects:
       - finite solid primitives: box, sphere, cone, cylinder, torus,
         heightfield, superellipsoid
       - finite patch primitive: disc
       - infinite solid primitive: plane
       - lights: point, cylindrical, spot, area
       - csg operators: union, merge, intersection, difference
       - atmospherics: background, skysphere, media, fog
   - Manipulate them (rotate, scale, translate, etc)
   - Manipulate and edit the camera
   - Render the scene with the multithreaded povray frontend
   - Create and edit materials (except slope maps), with preview in editor
   - Output the scene to povray
   - Save and load scenes, objects, materials
   - Save materials with preview in material library

WWW: http://truevision.sourceforge.net/