What are Homogenous coordinates?

What are Homogenous coordinates?



If w == 1, then the vector (x,y,z,1) is a position in space.
If w == 0, then the vector (x,y,z,0) is a direction.
(In fact, remember this forever.)

What difference does this make ? Well, for a rotation, it doesn't change anything. When you rotate a point or a direction, you get the same result. However, for a translation (when you move the point in a certain direction), things are different.

Homogeneous coordinates allow us to use a single mathematical formula to deal with these two cases.

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