I'm working in a scene where I want a logo to cast some glowing illumination on the objects/scene around it. When I crank up the luminance of the material to get the effect I want, the object itself obviously blows out and ruins the way I've go the material looking.
Is there a way to add this light emitting effect with out compromising the look of the object that is emitting it?
The closest example I could find of the effect i'm talking about is the Engadget logo:
There are two ways you can go about it: physically accurate with global illumination, or fake with a light gobo.
GI: obviously you have to turn on GI in the render settings. Once you've done that the luminance channel of your material will generate light. You can increase the light output without affecting the appearance by going to your material's Illumination tab and increasing the "Generate GI" strength.
Light gobo: with this method you create a material with an alpha that you place on a spot light. The material will act like a screen and cause the light to project in the shape of your alpha. It can be a bit fiddly as you have to adjust the material's projection accordingly.