PixelLight allows for applications to visualize any type of 3D scene within an application. PixelLight isn't a 3D engine but a framework to combine different components in a uniform manner while concealing the underlying library/API/OS. PixelLight is written in C++ and uses OpenGL while abstracting out the complexities. PixelLight has also been extended to handle sound, physics, network, and scripting.
Here's some screenshots of PixelLight in action for those interested. Embedded at the end of this article are also some videos made using this multi-platform open-source 3D framework. This open-source project that's been around since 2002 supports Microsoft Windows, Linux, Android, and even experimental support for Maemo 5. Besides desktop OpenGL there's an OpenGL ES 2.0 renderer. Via plug-ins there is also support for Qt, OpenAL, Newton, PhysX, LUA, and much more.
Those wishing to find out more information or to download the cross-platform 3D framework, visit PixelLight.org (at the time of publishing, the project web-site hasn't been updated for the v1.0 final release, but it's available).