Class 2 notes

Gobos
Place gobos by mapping the color slot of a light with a texture. This can act like a slide projector if you use a file texture, or just a way to break up the uniformity of light with a ramp or noise.

Dmap Shadows
Depth map shadows are quick and dirty when compared with ray tracing shadows. Here are some tips for getting Dmaps to do what you want.

Resolution should be powers of two in the range of 32 to 2048 pixels (square).

Auto focus may give you a crummy percieved shadow resolution if you have a large scene. Try overriding this focus angle yourself.

Filter size is what you can use to soften shadow edges. Try anywhere from 1 - 8.

Bias the shadow to cure self-shadowing artifacts.

Per object shadow cast & receive
You can selectively toggle shadow casting and receiving attributes on your models. This will speed up shadow tuning in many cases. Tell floors to not cast shadows and you'll avoid self-shadowing artifacts.

Directional and ambient lights
Generally speaking, don't cast Dmap shadows off of light types other than spotlights. They will either be slow or problematic. Ambient tends to flatten your scene; you can use low-intensity directional lights instead to add "ambient" lighting. Don't let these guys emit specular light, either, to further help the illusion.


Links

Shadow mapping

Lighting tutorial