Panda3D

Panda3D is an open source framework especially intended to be used for 3D rendering by game developers who work in Python and C++.
The game engine comes as an installer which you can deploy on your computer in order to obtain all the files and samples you need to get started. Panda3D depends on your graphics card driver to function and requires no compilation step.
It features full Python integration, OpenGL and DirectX features are exposed to the engine, you also get shader generation, 3D pipeline, physics modules, particle effects, GUI creation tools, performance monitoring, debugging and AI.
Cg, GLSL shader languages are available with this framework along with interfacing between shaders and the engine. It also enables the use of depth, shadow and stencil textures and supports multiple render targets.
With it you are able to import models from 3D modeling software and offers EGG exporters for Maya, Blender and 3ds Max. Conversion between multiple types of 3D formats and EGG is possible as Panda3D supports collada, x, .lwo, .obj, .dxf, .wrl and .flt.
Using this engine you can create realistic scenes because it provides physics simulation compatibility for engines such as Bullet, ODE and PhysX.
When it comes to patching up problems, Panda3D demonstrates a high level of error tolerance and supplies over 5000 assertion-checks meant to detect errors in early stages of development. Additionally, the framework offers for use optimization tools with the purpose of identifying bottlenecks for CPU and GPU, you can count meshes, textures, state changes and much more.
Panda3D is a rather complex game engine which consists of a very large number of features and tools aimed at developers with some experience behind them. However, if you stumble on something or need details about a component, Panda3D incorporates detailed documentation as well.