Well, I understood it pretty well and I found it really really cool so I can’t stand to start with it! 
Though I’m wondering how much work represents the calculation of an object complex collision… I just watched to one of an SM_Bush, that’s quite funny 
Also I tried to see the collisions of a BSP (Binary Space Partitioning) (the other alternative of object we tried) I’ve set in my scene, but… can’t find where this option hides :