4.2.2 Scaling

We can scale the vectors $v$ with a constant factor $w$, i.e. $v\mapsto w\cdot v$. In case $w=-1$ we have a point reflection. We can even scale with a vector $w$ by multiplying the corresponding coordinates by that of $w$, i.e. $v\mapsto \langle w_1\,v_1,w_2\,v_2,w_3\,v_3\rangle$.

Syntax in Pov-Ray: scale w

In case all coordinates of $w$ are $1$ except one which is -1 this is a reflection on the plane given by the set of points where the corresponding coordinate is 0. So for $w=\langle-1,1,1\rangle$ we get a reflection on the $y$-$z$-plane.