Sardtok, I was trying it using your method of rendering the light cone on black. So..., I duplicated my file, named it light cone, change all the objects in the scene to a pure black shader, no reflections,glow or anything. Turned ambient light to zero. I then did a render , composited with the colored rendering, it worked but the black areas that were supposed to be pure black or 0,0,0 for the RGB values were like 8,6,6. So when I use "add" as the merge mode I get areas that get brighter when they shouldn't . I could fix this in my image editor by changing the semi black to pure black but it would be nice if it could be all done in Carrara. Any thoughts and thanks for your previous help everyone.