Most of the Dynamic Hair that is offered for free, or for sale, is so huge in size, that it can be very hard, if not impossible to work with. Not only does it take longer to render but in so many cases, it is impossible to simulate using collision detection. The above animation consists of a hair and skull cap that total 384 kb's. Because of this, it is quite workable, and collision detection does indeed work. I have seen it said that if one decides to model clothes for Poser, that the mesh should be made as simple as possible. The same advice also holds true for Dynamic Hair.