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View Full Version : Volumetric yawn! zzzzzzzz



Otterman
11-29-2006, 06:55 AM
I have a scene lit approx by 40 arealights to mimic radiosity (NO Volumetrics). This renders within 2 minutes.

Now when I add one more light (spot) WITH Volumetrics, Render Times are nearing an hour. Is this normal or do I need to uncheck something. Is it calculating volumetrics for the other 40 lights as well even though Im thinking they are not ???

Ive tried checking "Sprite Mode" also and its no better! boooo!:thumbsdow

Skywatcher_NT
11-29-2006, 08:56 AM
Just render the volumetrics seperate.
So you have total control over it in comp.

SplineGod
11-29-2006, 12:05 PM
What kind of scene is it? 40 area lights is an awful lot. I would think those by themselves would take at least that long to render.

voriax
11-29-2006, 06:10 PM
Agreed with Skywatcher_NT .. render them separately. Volumetric lights have never played well with the other children. For me, at least.

Otterman
11-30-2006, 01:54 AM
This is gonna be an 360 flyaround animation so rendering separately is gonna be an After Effects-masking ball-ache of a process! Oh well- nothings that straightforward.

Just to ram home in my head,- what is the protocal for setting up a volumetric light.

1. create light (dont use linear or area lights for this).
2. check "Volumetric Lighting" within the Light properties.
3. check "Enable Volumetric Lights" in Global Illumuination (?)
4. render.
5. sit back and enjoy the delights of the perfect 30 second render! (ha!)

Hiya SplineGod- yeah, 40 area lights sounds excessive-its a similar the lighting rig illustrated on p566 of the lw[8] manual (dome effect).

Extent
11-30-2006, 04:49 AM
If you're doing a light dome I'ld skip the area lights and just use spots, that should speed your pre-volumetric rendertimes up even more. Just use a bit of the spinning light trick to smooth out the shadows, if you use soft shadow mapped lights it works even better.

Volumetrics can be massive rendertime hogs, the simplest way I can think of to tweak the settings to render fast would be to preview it in VIPER. Adjust the settings around and you should be able to get a feel for which controlls will slow down your render alot, then just try to avoid using them. With VIPER you can get a feel for how fast it's running while its in the middle of the frame, and you don't have to wait for it to finish to change things.

Compositing it in AE wouldn't take any masking at all. Either render out depth buffers for both passes (AE does depth compositing right?) or the simple way is to set all your objects as matte surfaces with no alpha channel. Then all you have to do is drop the volume pass right on top of the composite.