[Radiance-general] Applying materials & non-orthagonal surfaces

[Carsten Bauer]

Hi Mark !

Radiance provides the surface normal of the actual ray hit as Nx, Ny,
Nz. These data are accessible by the caculation engine evaluating the
cal-files, in the same way as the coordinates of the ray hit (Px, Py,
Pz) and some other stuff.

This means that you have to analyze in which way your texture or the
appearance to be produced by it depends on the surface normal, and then
adapt it to the new normal with help of the Nx/Ny/Nz values. (Generally,
this will be a rotation).
By this, the textures can be adjusted to the normals without having to
know the object on which they are applied.

-Carsten