Well it doesn't matter from where update() is called (as long as it is not when the canvas is rendering.
By "existing classes" you mean all those in com.xith3d.* and org.xith3d.* ? Shape3D isn't necessarily dynamic so don't need to implement GeometryUpdater or whatever.
Yaa you are right Shape3D isn't necessarily dynamic so don't need to implement GeometryUpdater
...it does'nt make sense to have unnecessary funtionality in the classes.
Hawkwind , thanks for pointing out the example,will go through this