Whow to create reflection matrix?

Ok, people, problem(if it’s problem) is next:
I have a transformation matrix and plane. Whow to create matrix thet will be identical to first one, only reflected to the other side of plane.
Does someone has an algoritm or site, that can do that.

Try this, it worked for me

Hope it helps


Thanks, Mark!
God, algorithm is so simple! Ihaven’t noticed this way. Ok, I am not very good in vector angebra… I guess I need good training.