heyas; where are you turning it on? collision detection in the pose room is supposed to make the models act solid, so you can't shove your hand into your head or anything. this kind of effect would be kinda subtle. such as: you turn a dial to poke yourself in the eye, and the dial stops turning at a certain point (where the fingertip meets the eyeball). displacement bounds has nothing to do with collision detection; that has to do with displacement map rendering. if you're turning on collision detection in the cloth room, you're setting up a specific set of circumstances for the cloth to interact with the figure or props or whatever in the scene. nothing will happen, however, until you run a simulation. also, if your cloth object is sticking into any models at any point, it will 'fall through' the object and not collide properly. if you're doing hair collisions... good luck!