Quote - Just a thought, why not use a spotlight to light the object you want darker with negative light?

 

Generally that's a pretty poor workaround, very hit and miss, very difficult to get just right. Once you add one negative light you find you need more because one can't quite do it, and before you know it you've simply compounded the problem and have also created more lights than OpenGL can display in the preview.

Not just that, but in alot of cases the idea isn't to darken an object, but rather to prevent other lights from affecting it.

See what was quoted above by Jeremy Birn - a negative light in that example would completely defeat the purpose of the effect he wanted.

 

It depends on your scene complexity though. It can work and I've done it many times, but it's almost impossible to get the exact lighting that simply having on/off otions for diffuse and spec for objects would give

...