DIF polys/collision

Hi all,

I have a need to perform a castray against DIF objects, and return the renderable polygon that the ray intersects. I know that with DTS objects the castrays are generally done against a seperate collision mesh. Since I needed to perform the same thing with DTS objects I had to implement my own castray method that did ray/poly tests on the renderably polygons.

But I don't know too much about how the Interior objects work. Is a castray on Interiors also done against a seperate collision mesh? And if so, how can I go about getting a list of the renderable polygons to do my own castray?

Thanks