Oriented Box collision detection

I want to direct your attention to two useful tutorials for developing a hierarchical based collision detection system.

The first link covers the OBB (oriented bounding box) tree - http://www.owlnet.rice.edu/~comp650/Spring01/presentations/OBB/OBBTree.ppt

The second covers a tutorial on the mathematics behind principal component analysis, which is useful to understand some of the mathematics in the OBB Tree paper: http://csnet.otago.ac.nz/cosc453/student_tutorials/principal_components.pdf

There are also two books I recommend as well. The first is Computational Geometry by Berg, Kreveld, Overmars, and Schwarzkopf, and the second is - as mentioned before - Christer Ericson's book Real Time Collision Detection.