trans or glass material, rectangular luminous opening problem

Gregory J. Ward wrote:

2. I have .ies data of a rectangular flood light and convert it into a radiance file. Although the resulting Polygon is glowing, the light output seems to come from the middle of the polygon and not from the whole area. Is this correct?

That is correct. If you set the -dj option to something between 0.5 and 0.8, you will sample over a larger subregion. (A setting of -dj 1 is allowed, but only works if all the sources in your scene are rectangular.)

Christian, are you referring to the appearance of the illuminance patch on a surface near the source, or rather the apparent brightness of the source polygon? If the former, this could be the result of having -ds set too low.

- Rob Guglielmetti