I have been experimenting with Radiosity and Raytrace in these examples using Ceiling Fixture 3. You may find some of the findings useful as what appeared to be a bug with this light (and Ceiling Fixture 4 also) was corrected by doing a full quality Radiosity render.
1. The first image is the simple 'Lights On' screen view - quite good really but no shadows.
2. This is Raytrace only - very quick but quite hideous shadows of the light fitting on the ceiling. The light source sits at the bottom of the fitting and if you reduce the size of the fitting the light source seems to stay in the same place so the shadows on the ceiling shrink somewhat. You can move the light source also of course.
3. This uses Radiosity also - at Quality Level 3 - the ceiling is totally black. Ceiling Fixture 4 had the same result. Full quality render fixed it.
4. Full quality render - black ceiling fixed.
Have not tried all the lights but some of the others gave light on the ceiling at Quality 3 but Ceiling Fixtures 3 and 4 needed the full quality Radiosity setting (in may tests)
Allan
