[JAVA3D] Picking problem

[Jason Stine]

I am working with an application that requires using a PickRay independent of the mouse or the viewpoint.  I want to be able to have a Java class generate x and z coordinates, set a PickRay's origin at (x, [very high above the scene y value], z), then use the utilities (PickIntersection) to get the y value of the first object picked. The problem is, my SceneGraphPath[0] is null, resulting in a null pointer exception.  I'm sure it's a simple fix like setting bounds or setPickable(true) on the objects in the scene (I've checked both of these).  Can anyone point me to an example that uses a PickRay not attached to either the mouse or the viewpoint?  The demo classes all refer to the mouse or the camera, neither of which is useful to me.  Thanks, Jason