Panda3D

Panda3D is an open-source, free game engine that Toontown Online was developed and runs in. It was developed by the Disney VR Studio branch of Disney. Panda is cross-platform and can be programmed in Python or C++.

Features

 * Rendering Engine
 * Python and C++ support
 * Cross-platform support
 * Networking support
 * 3D Audio
 * Collision Detection
 * I/O support
 * Physics System (not utilized in Toontown)
 * GUIs
 * Debugging Tools

History
Panda3D was developed by the Disney VR Studio initally for a 3D attraction at one of their themeparks, Aladdin's Magic Carpet. The primitive engine would later evolve into Panda3D. In 2002, the engine went open-source to make working with univerisities much easier.