Thanks, I check out the tutorial. Regarding ball, ASE is normally used to export the whole scene including many models in it (its too heavweight to use for a simple model like a ball which should really be a primitive).
I have many objects in the scene that I want to move around.
Why do you think ASE is "heavyweight"? I'm not sure if there is really such a significant difference between having several small ASE models and one large model. If you have the same materials several times, you save some bytes. What are other advantages?
If the practice is to export each as ASE, then can you load multiple ASE's into the same world? If yes, then how do you link them to the universe?
It's up to the programmer if he wants to have several small ASE files or one large file. Xith3D supports both. Loading several ASE files is easy, because you can insert them as BranchGroups in the scenegraph.