[Radiance-general] Re: Picture Mapping CAL File

[Greg Ward]

Hi Marcus,

I believe what you're looking for is defined in the main initialization 
file, rayinit.cal:

                         { Local (u,v) coordinates for planar surfaces }
crosslen`P = Nx*Nx + Ny*Ny;
                         { U is distance from projected Z-axis }
U = if( crosslen`P - FTINY,
                 (Py*Nx - Px*Ny)/crosslen`P,
                 Px);
                         { V is defined so that N = U x V }
V = if( crosslen`P - FTINY,
                 Pz - Nz*(Px*Nx + Py*Ny)/crosslen`P,
                 Py);

As such, you don't need to specify this file to use the U and V 
variables -- just put "." as a placeholder where the file would 
normally go.

-Greg

> From: "Marcus Jacobs" <marcdevon@hotmail.com>
> Date: December 14, 2003 8:00:02 AM PST
>
> Dear Group
>
> I remember in the past coming across a CAL file (not picture.cal) for 
> mapping 2D images onto 3 and 4 sided polygons. Does anyone know which 
> CAl file this is? I have been unable to find it.
>
>
>
> Thanks
>
>
> Marcus