Vray Environment Fog - Help? ^^

[cepheuss]

Hi guys!!

So heres the deal, i have got a huge travelling that ranges from 0 to 6000 in the Y-Axis. I've got around 20 V-Ray Rectangular Lights that have their intensity multiplier from 150 to 450 and have a size of 4 by 4 (UV). The scene is rich in geometry. Thing is it takes ages to render and i have been trying to solve this for the past 4h or so in vain.

How can i optimize vray fog?
How can i have a fog height of 6000 and still keep my fog render times healthy?
What are the things that make fog heavy?
How do the parameters of Density and Distance influence render time?
How does geometry influence it?
How do lights influence it?

Thank you very much!
Ceph

[Rens]

hi, standard max.lights spot or omni with attenuation help a lot

[cepheuss]

Thank you. But i forgot to precise i'm using Maya ^^.

[Morbid Angel]

Question is, does the scene render fast otherwise without fog?

Generally a few things I would check - can you make a small fog in sections and put those as gizmos in your scene? I don't really think fog would slow down the rendering that much, you need to put a lot of samples in to it. Also probably best bet to render it as a sep pass with all objects having just simple material and as matte objects.

[cepheuss]

1920x1080 render takes 9mins. Also i'm already rendering it in a different pass with meshes as mattes.

I just replaced the environment fog by a new one with the same settings and it seems to go a lot faster. (the node was probably bugged)

Thanks for all the answers! If not t would be awsome if you could help me out with the questions i posted in my first post !

Thank you!

Cheers,
Ceph

[Neilg]

e: sorry, just saw your post above. nm!
are you rendering the fog as a separate pass? having fog visible in reflections is a huge killer. we always render it seperately in a scene with glass deleted and reflection/refraction & glossy effects switched off. you can simplify or kill the GI then too.