Newbie question about Planes and intersection

Troubleshooting General Help
1

I can't seem to get intersection with a plane to work correctly. Right now I'm suspecting it's because I'm doing something wrong.



I want to have a plane facing upwards (Y-direction) at a certain height. I then want to find out where my predefined rays intersect with this plane.



Plane p = new Plane( Vector3f( 0, 1, 0 ), upperBound ) //Where upperBound is my Y-height 
r.intersectsWherePlane( p, loc2 );  // Where r is a ray that I know has Y-coordinates above and below upperBound



But I only get nullvalues in loc2. So my question is, where do I go wrong? What should I pass to the Plane constructor to get a upward facing plane at a certain height?
2

I just implimented this in my program last night…



This thread helped me a lot:

http://www.jmonkeyengine.com/jmeforum/index.php?topic=6057.0