For use in [[Perspective Projection]] / [[Clip Coordinates]], perspective division is when you map a homogenous point $\tilde{P}$ where $\tilde P_w$ is not one to its [[../Math/Homogeneous Equivalence|Homogeneous Equivalent]] [[../Math/Point|Point]] $\tilde P'$. $\huge \mat{ x\\y\\z\\w } \stackrel{\div w} \mapsto \frac{1}{w} \mat{ x\\y\\z } $