CGTalk > Software > Autodesk Maya
Login register
Thread Closed share thread « Previous Thread | Next Thread »  
Thread Tools Search this Thread Display Modes
Old 05-01-2013, 06:53 PM   #1
New Member
Random City, United Kingdom
Join Date: Nov 2011
Posts: 4
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
Old 05-02-2013, 09:13 PM   #2
Madness. Madness, I say!
InfernalDarkness's Avatar
Sho Pi
CG arch/viz
Seattle, USA
Join Date: May 2008
Posts: 5,633
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?
Commodore 64 @ 1MHz
1541 Floppy Drive

"Like stone we battle the wind... Beat down and strangle the rains..."
Old 05-03-2013, 07:25 AM   #3
Care bear
VFX artist - 3D
Malmö, Sweden
Join Date: Dec 2005
Posts: 636
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."
Old 05-03-2013, 07:25 AM   #4
CGTalk Moderation
Lord of the posts
CGTalk Forum Leader
Join Date: Sep 2003
Posts: 1,066,479
Thread automatically closed

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.
CGTalk Policy/Legalities
Note that as CGTalk Members, you agree to the terms and conditions of using this website.
Thread Closed share thread

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Society of Digital Artists

Powered by vBulletin
Copyright ©2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump

All times are GMT. The time now is 01:53 AM.

Powered by vBulletin
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.