The so3DTools aims to provide many different helper class, examples and tutorial in C++ for OGRE3D. It aims to make understand how to use some advanced features in OGRE 3D. It is LGPL. At 2011/03/28, the project contains 20 tutorials + Ogre.chm.
The eXtensible Resource Interchange (.xri) file format was written to provide a standard, open 3D model format. It is designed for use in real time computer graphics and is compatible with current 3D graphics technology.