Fog tips

[Macker]

Hey chaps,

Just wondering if any of you have some pointers or advice when it comes to adding fog to your scene using the Vray Environment Fog? Do you bother with gizmo's? What kind of settings do you generally arrive at? And so forth. Do you find it pushes your render times through the roof, as I have? Am I doing something wrong?

Any help/tips/advice is much appreciated.

[Morne]

Hey chaps,

Just wondering if any of you have some pointers or advice when it comes to adding fog to your scene using the Vray Environment Fog? Do you bother with gizmo's? What kind of settings do you generally arrive at? And so forth. Do you find it pushes your render times through the roof, as I have? Am I doing something wrong?

Any help/tips/advice is much appreciated.

Good old Peter to the rescue:

http://forums.chaosgroup.com/showthr...770#post413770

and

http://forums.chaosgroup.com/showthr...916#post413916

[RockinAkin]

Rendering Fog separately as it's own pass is the best approach for maximum control in post and drastically cutting down on render time.
Just set everything in your scene to a black material, turn off GI if desired, and only render the Fog.

[Neilg]

yeah i'm also one for doing a separate scene for fog. trying to do it in a main scene is a waste of time imo, takes forever to balance a result that still isn't as good as something you could have comped in 1/10th the time.
Because my camera is usually open and all the nice rays happen in the distance i'll make some huge black planes floating in space to block the light in certain areas, otherwise it ends up way too hazy. using multiple small gizmos so it only happens in certain areas is also the way to go. The sun/lights usually end up significantly more powerful than in the main render too.

[Seraph135]

I'm totally in agreement for having the fog in a separate pass...However, if your scene is fairly reflective then you may have a serious mis-match when you later comp the final beauty render. I've run into this problem on several projects and was forced to render the fog as part of the main beauty render. Even though it takes longer I generally like to render them together if I have the time so that I get all those nice realistic interactions. What bugs me is that I still have to render a separate pass just to get the proper alpha channel for the fog so that I can comp it correctly, and that multimattes are affected by the environment fog. At least in Vray 2.40.04.

I've found that if I'm going to be rendering fog then it really helps to crank the subdivs up high on the fog and raise your max AA higher than usual as well to give Vray some extra room to be adaptive with it. Also, instead of assigning a black material to everything. I just disable maps and reflections in the global switches and make everything matte -1. That way I get a nice alpha channel for the fog as well and don't have to worry about material overrides.

Tim J

[Macker]

Thanks for the feedback chaps. Do you guys have any "general" settings that get you in the right ball park to begin with, or do you start a fresh every time?