Wall Worm Model Tools
The Wall Worm Model Tools (WWMT) is a MAXScript utility to help you send your models from 3ds Max to Valve's Source Game Engine. The purpose is to make the process go faster. If you've ever made a model for the Source Game Engine, you know how much of a drag it is--all of the work comes after you've designed your model.
With WWMT, there is no more need to write QC and VMT files in most circumstances. With WWMT and the VMF exporter, you can even output your models and level all at once!
Here are some pages to help you learn more about WWMT:
The bone tools allow you to give specific bones artbitrary surface properties, set mass bias and create hitboxes and hitbox groups.