What is the best way do do an intersection (hitscan) test for a beam weapon against a 3D triangle. It needs to determine the XYZ position of the intersection.

What is the best way to do collision detection between freeform polygon objects (i.e. not bounding boxes).

-Denix Linelli

For a beam weapon, you presumably want to do a ray vs. triangle test. Check out this article in Graphics Gems 1: "An Efficient Ray/Polygon Intersection", by Didier Badouel.

As for collision between polygonal meshes, that's an entire field in and of itself.