Reflection of a Point in a Plane
For point:
$$P(x_1,y_1,z_1)$$
and plane:
$$Ax+By+Cz+D=0$$
let:
$$S=Ax_1+By_1+Cz_1+D$$
The reflected point is:
$$P'\left(x_1-\frac{2AS}{A^2+B^2+C^2},y_1-\frac{2BS}{A^2+B^2+C^2},z_1-\frac{2CS}{A^2+B^2+C^2}\right)$$
Usage
- Used to find the mirror image of a point across a plane.