### 4.1 Exporters

Exporters are plugins to 3D modelling tools which write meshes and skeletal animation to file formats which OGRE can use for realtime rendering. The files the exporters write end in .mesh and .skeleton respectively.

Each exporter has to be written specifically for the modeller in question, although they all use a common set of facilities provided by the classes MeshSerializer and SkeletonSerializer. They also normally require you to own the modelling tool.

All the exporters here can be built from the source code, or you can download precompiled versions from the OGRE web site.

### A Note About Modelling / Animation For OGRE

There are a few rules when creating an animated model for OGRE:

- You must have no more than 4 weighted bone assignments per vertex. If you have more, OGRE will eliminate the lowest weighted assignments and re-normalise the other weights. This limit is imposed by hardware blending limitations.
- All vertices must be assigned to at least one bone - assign static vertices to the root bone.
- At the very least each bone must have a keyframe at the beginning and end of the animation.

If you’re creating non-animated meshes, then you do not need to be concerned with the above.

Full documentation for each exporter is provided along with the exporter itself, and there is a list of the currently supported modelling tools in the OGRE Wiki at http://www.ogre3d.org/tikiwiki/tiki-index.php?page=OGRE+Exporters&structure=Tools.