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Fog very noisy?

Posted: Tue Oct 04, 2016 4:29 pm
by MadsBroni
Hello there,

so I've just started playing around with the fog in the environment tag. I am going fog this cold, foggy look, but I seem to get very visible pixels even with 10.000 frames. Since this will be video, I need to figure out a way to render it less than 15 minutes per frame. Here is an image of the scene, and as you can see is there quite a lot of noise. I've tried hotpixel removal, but does not seem to help with fog active. Upping the samples helps, but even at 10.000 it's still quite visible. I've played around with the density and thickness, but can't seem to solve it.


Perhaps there is a smarter way of rendering a pass and do it in AE? I'm at a loss.

Hopefully someone can help me out. Thanks!

/Mads

Re: Fog very noisy?

Posted: Tue Oct 04, 2016 4:55 pm
by MadsBroni
A follow up question:

Is it possible to export the fog as a seperate pass?

Re: Fog very noisy?

Posted: Wed Oct 05, 2016 7:42 am
by bepeg4d
Hi MadsBroni,
What kernel are you using?
Could you share a screenshot of your settings?
Currently is not possible to have the environment medium in a separate pass. In general, the Z-depth pass is used to compose the fog in AE or similar apps.
ciao beppe

Re: Fog very noisy?

Posted: Wed Oct 05, 2016 9:23 am
by MadsBroni
Hi Beppe,

thanks for looking into this.

I am using direct lighting, but the problem is the same with pathtracing and PMC.

Here I've attached a screenshot of the settings + a z-depth pass. The z-depth pass doesn't seem to do what I want. I want it gradually to follow the depth, like the blur in the first image I put in this post. Is it possible to change the depth sensivity?

Re: Fog very noisy?

Posted: Wed Oct 05, 2016 9:29 am
by MadsBroni
I did fool around with the Z-depth max settings, and this is how it looks in the viewport. However, when I export it comes out as above, with pure black and white.

How do I get the same result as in the viewport?

Re: Fog very noisy?

Posted: Wed Oct 05, 2016 9:57 am
by bepeg4d
Hi MadsBroni,
make sure to set Tonemapped in the Tonemap Type:
Screen Shot 2016-10-05 at 11.56.07.jpg
ciao beppe

Re: Fog very noisy?

Posted: Wed Oct 05, 2016 12:36 pm
by MadsBroni
Thanks a lot Beppe!

Once again, you solved my problem. I will add the fog in post, and use the z-depth now :)

Really appreciate your help!

/Mads