How to put a Collision solid in model before importing?

Hi,

How do I put a collision solid in a model before importing to .egg file?

I was told it was possible on the Panda3D Sample programs - Ball in Maze, and read up on the ball.egg and maze.egg codes.

But I still do not know how do they do it?

HELP! Reply asap.

Many Thanks. :smiley: