Use of blender Import and Export Scripts:
This Tutorial is base on Blender 2.48, and this version is probably mandatory.
Scripts will be updated followind blender versions.
Export window will look like this:
Here is options usage:
Set: Will save all scene objects, independently of selected state of the objects.
: Only selected objects will be saved. If no object is selected, all objects are saved.
Set: Each mesh will be saved in his own file. There will be as many file as mesh in the scene.
Unset: All meshes will be saved in the same file. Be really carrefull about mesh center. Object position is not used in this case. So each mesh will be saved to it's relative corrdinate (normaly centred on 0,0,0) all mesh may fall in the center of the scene. Same mesh is exported only once. So if the scene include several objects linked to the same mesh it will be exported only once.