"Is there a mechanism that does simple Rotation behaviors like Java3D? If on each frame I want an object to rotate on its Y axis by a specified amount, how do I do that? SpatialTransformer, suggested in another thread, seems more complicated than I would think necessary for a replacement to RotationBehavior."
SpatialTransformer is more complicated because it does more than RotationBehavior for Java3d. You can use it for a simple rotation if you want. If you want help, I can show you how to make a basic rotation behavior Controller from scratch.
I would be interested in seeing how this is done in jme.
Currently, Controllers and what they are attached to have no significance. You could attach the controller to the root node and it would do the same thing if setup the same way. Controllers are being removed for another animation system this release of jME. Currently, there is no way to say "do this on all the children" without writting your own update function, which isn't very difficult in itself. I can help with this if you want. Controllers aren't objects in the scene graph. They are a seperate property of the objects themselves. This seems to be one point of confusion.
Interesting because I just expected them to be scene graph objects so I'll be greatly interested when they change. Is this in CVS now? If so I'll do a cvs update and play around with that
"By Attaching the transformer to the 'root node' I expect I should be transforming everything underneath."
The controller won't animate what it's not been specificly told to animate. ControllerNode type behavior is planned for the next jME release. I agree this system isn't best and that's why it will be gone on the next release.
Now you're just teasing me
Whats the estimated time for the next release?
Modeling a solar system with sun->earth->moon is more complex than it seems at first. You can't just attach them as children and rotate the moon around the earth because the earth is actually doing two rotations: rotating around the sun (year) and rotating around its core (days). So if you rotate the earth to represent days and the moon is a child you end up with the moon rotating around the earth really fast. You have to setup a center of rotation type system with a center of mass that the earth and moon can rotate around. I've actually coded this exact thing before and posted the code on the jME forum. I'll check my home computer and see if I still have it.
Cool. Would be interested in chatting with you as well. if you're open to some chatting, please PM communication options or just contact me. I think mine are public.