non homogeneous fog

[micmac]

Hello,
I try to render a automne scene with fog. I want to achieve a foggy mood but not homogenous...
Is there a way to achieve this affect? The picture attached is just an exemple!
thanks!

[romullus]

Not really. But i encourage you to go to this poll and give your vote for non-homogenous volumetric implementation. Currently it's pretty undervoted.

[Fluss]

Not really. But i encourage you to go to this poll and give your vote for non-homogenous volumetric implementation. Currently it's pretty undervoted.

Where is it ?

[micmac]

https://forum.corona-renderer.com/index.php/topic,96.0.html

[romullus]

Yeah, sorry, i forgot to attach link.

[TomG]

In the meantime, could render a World Position pass (CGeometry_WorldPosition render element) and use that in, say, Fusion to add 3D fog in post. I have a tutorial about that which ought to be live sometime soon (we've got quite a few tutorials coming out at the moment!)

Thanks!
   Tom

[maru]

Yes, there is a way to do this - just use 3ds Max native environment effects (fog, volumetric fog). It can be used to produce really nice results.

[Jpjapers]

Can someone explain what is meant by 'non-homogenous' fog?

[romullus]

Can someone explain what is meant by 'non-homogenous' fog?

As far as my understanding goes, it's when volumetric properties can be controled by map in all 3 directions, not only in X and Y. I may be very wrong though.

Yes, there is a way to do this - just use 3ds Max native environment effects (fog, volumetric fog). It can be used to produce really nice results.

I always thought that native enviroment effects does the same thing as Corona's volumetrics. Is there substantial difference in their behaviour? Might be worth to give it a try.

[FrostKiwi]

Can someone explain what is meant by 'non-homogenous' fog?

Different fog intensities in different volumes.

Basically an Opacity map for your Fog, but in 3D, so you can produce results like in the first photo, without creating a mesh from a fluid sim or similar workarounds.

[pokoy]

From my tests the Max fog doesn't get any shading from Corona's lights or environment, it's just a correctly blended illuminating something, but certainly not true volumetric fog. Am I missing something?

[mraw]

max's fog can produce really nice results- but under it's hood it is a post-effect, right?

[Jpjapers]

Right so you can get the change in density from say the water surface and up on the z axis??

[FrostKiwi]

Right so you can get the change in density from say the water surface and up on the z axis??

Check here for V-Ray example.

[PROH]

..or check here for Corona example (at 45sec):

It works pretty similar as with mr. Which means that it's working best with exposure set to 0. But Rawalanche shows a nice trick in the video: Use a CoronaSky-Map as fog-map. This gives you some control over the brightness of the fog.

Note that it renders slow.