vray noise on fog is extra slow

[thanulee]

Hi, im fiddling with env fog very long time and i cant seem to conclude what is the best way to use it with noise without killing ur render times. I got 2 teapots no materials, a small area light and fog. Without noise with my current settings, does 15 seconds. With noise goes wayyyy up to 8 minutes.. and my settings are pretty low. Any tips? Plus i cant see my other render elements they appear black when fog on. Only the atmosphere element has information in there.
Here is the max scene as well https://www.dropbox.com/s/7wnf8fpqwo...oblem.max?dl=0
thanks in advance!

[Morbid Angel]

yup I've encountered the same issue. Try reducing the threshold for texture sampling inside the fog shader.

[thanulee]

thank Dimitry. Still though i have no clue how to control it. I read in the manual that once i have textures, i control em with the texture sampling which overrides the generic samples in fog. I am at 8 samples though, its nothing crazy. This is far from logical in my mind. And the difference is huge is not like double time.

[Morbid Angel]

So if you adjust the following params it should be faster:

try first raise the threshold from 0.001 to 0.1 and see what you get.

[nils_p]

Up the step size like 10 or 100 times your current value

[LudvikKoutny]

Yep, step size is the main performance driving parameter here. Just keep increasing the step size value until you start to observe some artifacts and loss of detail. The value right before artifacts/loss of detail starts to occur is usually the sweetspot.

[thanulee]

Thanks guys. My settings are dead low in fog. I do not think this is normal. The area where light hits has the most delay. Anyways i bumped up my step size to 400cm while my overall distance is 450cm and i increased the cutoff to 0.01. It does 45 seconds less...
Here is the screenshot with my latest settings. How can i setup anything for production if with such low settings fog is sooo slow? Can someone check the scene see if i have screwed something up? thanks a lot for the replies.

edit: with max subdvs 1 does 45 seconds while it should do 10...

[svetlozar.draganov]

Can you re-attach the scene? The link from first post of the thread no longer works.

[thanulee]

Sorry deleted it by accident in my dropbox. U can recreate it though is just 2 teapots and a plane light. I ll try it again probably.

[thanulee]

Also, another question. How would u deal with large environment scenes? Fog or a gizmo covering my scene? Aerial perspective wont cut it, i need the "smoky" effect in fog.

[Vizioen]

Svetlozar, this was the scene. See attached. fog problem.zip

Also Thanulee; you might know this tutorial already but I found it very usefull: http://www.the-boundary.com/blog/201...-08-atmosphere

[thanulee]

Thanks a lot for all the help guys. I ll give it a look, i ve seen in the past i think. Well one thing i noticed, is that its like step size, closely related to noise size. Like u have to find a ballance between those 2 values. Still not totally controllable, but going somewhere. If also someone check the scene i ll be grateful. Cheers