Faking GI is simple enough if you just want to have an image of a pen on a desk, but for an outdoor scene, how do you prevent the black ring from the ends of the spotlights? If I move the spotslights too far out, you run into great trouble with shadow buffers, etc.
You just have to increase the distance of the spot light, as far as I know. If you make the spot light go completely through your ground plane, there should not be any black edges, (and I knw the ones you mean).
Try that and see if it works. Has for me.
The longer you make them, the more you have to increase your shadow buffer I believe, or the shadowing wont look very GI.
Also, the closer to the ends of the dome the brighter the light will be, creating un-realism. At least in my trials when I view the floor plane.
Maybe fall-off should be adjusted as well?
hmmm… that might do it.
It also helps to increase the SpotBl value. So you avoid sharp edges of the light cone - it fades out. Normally I increase the value to the maximum.