Mapping for FPS

Are there any really easy ways to map things like Dust in Counter-Strike? For my physics-ball game, I'll need to have contained spaces, completely indoors, so I wanted to map like how Counter-Strike does.

Has anybody written an importer for Hammer's files?

Or is there another alternative that's tried and true?

I think I’ll try this, and see how the physics works in those levels. I’ll let you know how it worked out.

I think I'll use MW3D actually…