This week, I continue my implementation of CollisionHeightfield by implementing collision tests from box and from sphere. Much of this week consisted of conducting research to find box-triangle, box-box, sphere-triangle, sphere-box intersection tests. Using Christer Ericson's realtime collision detection book, I was able to implement those intersection tests into CollisionHeightfield. Having those tests available, I was able to complete box collision test and sphere collision test. My next step is to do some bug fixing, writing extensive unit tests, and adding BAM serialization. BAM is one of Panda3d's native file format, and implementing BAM serialization allows a user to import/export the CollisionHeightfield from/to files. I would also like to make the sphere collision test more efficient by implementing Bresenhaum's circle algorithm, which will reduce the number of triangles tested. Hopefully I will be able to add some extra features, such as a collision test from capsule. In the final two weeks, I will be looking forward to making a sample game that demonstrates the use of the new CollisionHeightfield class. See you next week!