Papervision 3D Programming Tutorial: Mouse Picking
Here you can learn how to select a plane (which represents a photo) that is rotating slowly around a central point, using a little function called hitTestPoint2D, which enables to pass in the mouse coordinates and get the DisplayObject3D (if any) that lies directly underneath. Once selected the photo is brought to the front and displayed. Most of the work is done in the PickableObjectManager onMouseDown function, and the Picture enterFrame function. You can also watch the demo and view the source code.