This week, I started to implement the CollisionHeightfield class. My implementation is based off of Tim Sjostrand's "Efficient Intersection of Terrain Geometry in Real-Time Applications". The idea is to reduce the amount of polygon intersection tests by dividing the heightfield into smaller sub-rectangles using a quadtree data structure. So, collision tests with the terrain will resemble a box intersection test, followed by a triangle intersection test. This week, I successfully set up the quad tree, and made good progress in the ray-terrain intersection test. Next week, I will be finishing up the ray-terrain intersection test and starting the box and sphere intersection tests. The highlight of this week is setting up the quad tree, because now the intersection tests should resemble intersection tests that Panda already supports (box, polygon, etc). See you next week!