ABSTRACT
The first item is important if memory usage is an issue, either because we are working with a memory-limited machine such as a console, or because we want to store a large number of transformations, such as in animation data. In either case, any reduction in representation size means that we have freedup memory that can be used for more animations, for more animation frames (leading to a smoother result), or for some other aspect of the game. Rotating points and vectors efficiently may seem like an obvious requirement, but one that merits mentioning; not all representations are good at this. Similarly, for some representations concatenation is not possible.
