Vectors are used to represent a lot of things. The direction a vertex points for when you're doing lighting. The direction a face points, for hidden surface removal. The speed and direction your objects in your game are moving. The TFormVector TFormPoint and TFormNormal commands are very powerful and allow you to transform/rotate/scale vectors and points from one space into another. In other words, when you drive you car, it always moves along IT'S Z axis, but it does not always move along the Z axis of the WORLD. The car and the world have different coordinate spaces. All vertex positions for the car are in car space.
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