I am given a point (Px,Py,Pz) and a normal vector (Nx,Ny,Nz). I have to find the purple point (Tx,Ty,Tz) in this diagram:
illustration http://snag.gy/kLvIZ.jpg
The black line is a plane that intersects the origin (0,0,0) and is perpendicular to the normal. How can I find T?