Collision mesh

I have an .egg file that contains the terrain of my game. It has mountains and it is an uneven terrain. How could I include the collision mesh into my .egg file. Is there a way to do it manually? What other options do I have. I basically have a car that is being driven through this terrain.
Thank sooo much!

You basically need to add a tag like { Polyset keep descend } under the in your .egg file. This will copy all of the geometry under that group and turn the copy into collision geometry. (If you have separate geometry for the collisions, you may set this tag on only your collision mesh and omit the “keep” flag.)
This can sometimes be done in the modelling program. Which modelling tool did you use to generate the .egg file?