# what's the general form of 3D projective mapping?

I know that the general form of a 2D projective transformation is following rational linear mapping: $(u, v) \mapsto (x, y)$

$$x = \frac{\mathit{a}\mathit{u}+\mathit{b}\mathit{v}+c}{\mathit{g}\mathit{u}+\mathit{h}\mathit{v}+i}\\ y = \frac{\mathit{d}\mathit{u}+\mathit{e}\mathit{v}+f}{\mathit{g}\mathit{u}+\mathit{h}\mathit{v}+i}$$

What is its 3D version?

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