"Connor Pyles" <firstname.lastname@example.org> wrote in message <email@example.com>... > Say I have a plane given by a matrix M containing 3 points, and a fourth point like this: > > M = [P1x P1y P1z ; > P2x P2y P2z ; > P3x P3y P3z ]; > > P4 = [P4x P4y P4z]; > > What is the easiest way to mirror the fourth point across the plane? > > Thanks, > Connor
A plane is defined by the equation
dot(X - X0,N) == 0
where X0 is any point in the plane, and N is the normal vector to that plane. Here
will suffice. You can get the normal vector from a cross product.
N = cross(P1 - P3,P2 - P3);
Normalize to have unit norm to make things easy...