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View Full Version : Light behind cube shines through corners?

Activator
11-09-2007, 08:45 PM
Hi. I was wondering why a Spotlight, set to Volumetric with Shadow Maps, would shine through the corners of a closed cube?

Camera is inside the cube, light is outside. There are different textures mapped to the walls, but it is one object.

See attached render.
Per-Anders
11-09-2007, 09:03 PM
Because of the shadow bias. The shadow bias is a method of making the soft or shadow map shadows start a little behind where they're actually cast from, this helps solve the problem of artifacts from the shadow being visible on the surface that's actually casting the shadow itself if it's at an angle to the light source.
Activator
11-09-2007, 09:08 PM
Is there any way to prevent this? I tried disconnecting the back wall and making it a little bigger, but that didn't help.

My goal is to cut a hole in the back wall - a shape, or a word - and have the rear light shine through the cutout. It won't look right if the light is leaking from the corners.
Per-Anders
11-09-2007, 09:11 PM
Well you can just adjust the shadows bias, or you could give your box a decent amount of thickness (in all directions, there needs to be a thickness like a wall rather than like some cubes stuck on the outside). Though for what you're describing, why not just use inverse volumetrics on some text (not cut out)?
Activator
11-09-2007, 09:13 PM
Per-

Thanks for the tips. I'm going to try them but, for now, I fixed it by switching to Area shadows. (Which look SO good!)

Thanks!
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11-09-2007, 09:13 PM
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