blocking light out and letting it in
 

I am doing a scene where I have a light fog going through a window and I want to define it to just the window part. Right now it is going through the geometry around the window also. Is there some kind of gobo I could set up so it only goes through the window. I also would like to put glass so fog goes through it, but it just blocks it from showing.If I make a transparency map on the glass will the light go through then?Need help please.

I posted here because more people look in here than lighting and rendering I think.

Hey there Banksta,

I'm not sure if it's what you're after but I made THIS a while back and it might help.

It's all in the raytrace shadows!

Take it easy,

Mat :)

hi Mat,

That isn't exactly what I was talking about. I actually want the fog to only go through the window, But in a box shape like the window.Is the a cutout I can map to the light where it will allow only light to pass through the box shape of the window itself and not spill through the sides of the wall. Other than that the tutorial was informative, thanks for the info.

Use the barn doors option on the spotlight. You can look thru the light in another window and adjust them accordingly (MMB)

Fog only tends to work properly with depth map shads too...

_Jay

i'm not sure if this would help. you can link the light and the object!! this way, wht u r doing is telling the light to fall only on the targeted object and not to other objects in the scene. Try this

I think if you take HappyMats approach and tweak it a bit you can easily get the result you desire if nothing so far has worked.
If you take a plane that is bigger than the box, with the same window opening in it, and put it infront of the window. turn on shadows for the light so that this plane will only let light through the hole. Then in the render settings turn it to a non renderable item and the light will act as though it is there but it will not render.

Does that work for you?

-Alexander