View Full Version : Light Rays (God Rays) outdoor scene

06 June 2012, 09:52 PM
Good afternoon!

I have a question and I need a hand. I got asked to do a project and I'm running into a wall. I've been trying to create very slight god rays to pass through the text, and I'm having a heck of a time. I'm using Maya 2013 and Mental Ray. I have used and tried the Parti_Volume and transmat procedure, but it give was to much haze over the entire scene. I've also tried the standard Spot with Maya fog, and it doesn't seem to do the trick either... and both take WAY to long to render. Is there another way to do this? A better package that I can export the scene to? I should mention that I'm using HDRLabs sIBL for the background and over all lighting of the scene. Any suggestions would be greatly appreciated!

06 June 2012, 09:55 AM
I don't know about maya, but in max I usually render my volumelights with scanline and composite them on top in post. I recently went from 1 hour 30 min rendertime(everything in one with MR volume) to 30 min + 2 minutes(scanline volume), so it can save you quite a lot of time ALSO you get a lot more control since you can adjust colors, intensities and more seeing the adjustments instantly with no re-rendering needed.

06 June 2012, 05:14 PM
I'm giving that a try... I can't seem to get the effect I'm looking for. The light fog doesn't seem to penetrate the holes in the text. The only way I've gotten it to work is through the parti_volume. Cant find a set up for maya and scanline volume rendering so I was winging it. O.o

06 June 2012, 07:05 PM
This what I managed to produce... Still used the Parti_Volume and took forever, but it doesn't look to bad. I went with this option because I wanted to get accurate sun light rays. I think it did the job... looks like a hot summer day in New Orleans

06 June 2012, 11:16 PM
Hi, I don't know if you're still working on this but I would encourage staying with the parti_volume workflow for any subsequent attempts. It's a great way to make physically accurate volumetric effects but it's rather slow. One thing I would recommend, especially if you're rendering a movie and/or using final gather is to make a separate render with just the light rays and black objects (turn off final gathering in the volumetric effect pass). You can comp the effect in afterwards, and the renders will be much quicker.

I recently created a tool ( to help with the parti-volume setup, if you're interested you can give it a go.

CGTalk Moderation
06 June 2012, 11:16 PM
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.