I've been living in 3D space with Avalon, which can be disorienting to say the least. There is this constant question of "where am I"? All is relative as far as model space and world space. The key to 3D is knowing where "you" are, such that actions like transforms and camera moves make sense, which brings me to the I Ching. In Ta Chuan [The Great Treatise], there is the following:
For in regard to any change there must be some fixed point to which the change can be referred; otherwise there can be no definite order and everything is dissolved in chaotic movement. This point of reference must be established, and this always requires a choice and a decision. It makes possible a system of co-ordinates into which everything else can be fitted. Consequently at the beginning of the world, as at the beginning of thought, there is the decision, the fixing of the point of reference. ...The ultimate frame of reference for all that changes is the nonchanging. 
Sound advice when doing matrix math in 3D space.
By the way, if you are looking for an excellent online version of the IChing, see http://www.lensgrinder.com/ and follow the link "Application."
 The I Ching or Book of Changes. The Richard Wilhelm Translation rendered into English by Cary F. Baynes. Page 281.