It sounds like what you want is not "A LIGHT FITTING" (like "a chandelier")
What you want is like "SOME LIGHT FALLING ON STUFF"
In other words if I pointed a spotlight on a floor, that would be a "circle of light" on the floor -- what you want is a "donut of light"
Is that correct?
If so, I have your answer. You have to learn about "Projectors"
If you look at blob shadows, that is exactly what a projector is.
In your project, look around for the free standard assets that unity gives you.
Add a projector, blob shadow. In fact, ther eis indeed one that is a "shadow" (it's dark) and there is one that is a "light blob" .... which is exactly what you are asking for, I believe.
the only difference is you want a particular shape (a donut) rather than just a circle.
From here, you will have to do the work to figure out how to make it your own custom shape! I hope, that helps!
FTR earlier answer,
Just use a "self-illuminated shader"
If you don't need the light to move in the scene, make a mesh torus, give it a light emitting material and bake it with the lightmapper. If you do need the light to change in the scene, give it a point light in the middle. An area based light is too complicated to run at runtime (at the very least without some complicated shader-fu)
answered Jun 03 '12 at 01:29 PM