I found the applet below on this webpage. I think their solution for moving objects in a 3D graph is pretty good, and in some ways better than moving 3 sliders.
I would like to mimic this functionality. Notice you are allowed to drag the the ball without the 3D view of the graph changing. You can only move the ball within its current plane but I still think its worth it. Notice when you drag anywhere else (off the ball) the viewpoint of the 3d graph changes as usual.
How would I go about doing this? It seems I would have to disable the view while I'm moving the ball, but not sure how to move the ball since locators are only in 2d. Ideas?
*I am dragging the object with my mouse in the gif. You can't see my cursor unfortunately.