How about not representing the Normal as an absolute entity, but rather as a point relative to one of the vertices in your poly. This way you could simply transform the "normal point" with the rest of the poly. Obviously you'd need to subtract the two points (in either world or perspective space) to get the actual normal. (If that's an issue, and memory is not, you could store both)...

/Niels

If I have a polygon and have calculated the normal to the plane formed by the vertices of the polygon, when I perspective project those vertices from 3D to 2D is there any way to project the normal as well. What I would like to do is be able to find points along a line normal to the plane formed by the vertices of the polygon AFTER perspective projection.

thanks for the help

Eh! I think I got "absolute" and "relative" reversed in that post Hope you get the point anyway

/Niels