Megahedron Pros

• On-line documentation is provided.
• Supports object import of various formats through its ``extensibility''.
• Wireframe modes support a form of hidden line removal that cleans up the wireframe displays.
• Supports 3D stereo anaglyph rendering (red and blue stereo pairs).
• Collision detection for animation.
• License is fairly unrestrictive--one user, many machines. Not freely redistributable, but that's expected and acceptable with commercial packages.
• Capable of network-based rendering.
• Matrix math seems fairly easy to use:

v1 dot v2 = vector 1 dot product with vector 2