Volume Fog - Ray Tracing Shadows

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  05 May 2013
Volume Fog - Ray Tracing Shadows

Hi, I'm currently working on a college project, the idea is an abandoned asylum and I'm using volumetric fog to create a darker atmosphere.

My issue is that the environment will be presented as though someone is exploring with a flashlight, so shadows are a going to play a huge factor in how the scene looks. The problem is that when I turn my spotlight on to use Ray Trace shadows, It also affects the volumetric fog, which gives it a horrible noisy look to it - At least I think that is what is happening, it's the only change I make when I try to render.

Is there a way to disable ray tracing for the volume fog?

I've taken a couple of pictures to demonstrate my issue.

With ray trace disabled on the spot light:
(This is more or less what I want)

With ray trace enabled on the spot light:
(shadows seem to emit from the volume noise)

Any help would be great
  05 May 2013
This is normal for raytraced-shadows through a volume fog.

Are you rendering with mental ray? If so, to get accurate volumetrics you'll want to use the parti_volume shader, which can be a real chore to set up and will vastly increase your rendertimes, as well.

You could disable shadows on your volume fog, possibly?
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  05 May 2013
You can try fluids as well. They don't really take longer to render than the parti_volume and you get instant feedback in the viewport.
"No, the movement is good, it just has to travel faster from spot A to spot B in the same amount of time."
  05 May 2013
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