If i have 3 points on a plane (p1, p2 & p3), how on earth do i find the distance from the plane to the origin. Alternatively, how do i find the intersection of 3 planes defined as 3 points? Background Info: I''m trying to convert Quake maps to my own format, and brushes are stored as lists of planes (defined as 3 points). To get the vertices from a brush, i need to find the intersection of 3 of the planes, and loop till ive tested every plane against every other plane. Cheers, Steve

Find the plane equation. Ax+By+Cz+D=0
Then D is the number you''re looking for.

To get the plane equation, take the cross product of two vectors made from your 3 points to get the plane normal. Then you have A,B,C, x,y,and z, solve for D
(A,B,C) is the normal of the plane
(x,y,z) is any point on the plane