PLANENORMAL Compute the normal to a plane.

   N = planeNormal(PLANE) 
   compute the normal of the given plane
   PLANE : [x0 y0 z0 dx1 dy1 dz1 dx2 dy2 dz2]
   N : [dx dy dz]
   
   See also
   geom3d, planes3d, createPlane

Package: matgeom