GI noise reduction?

[ShaunDon]

Morning all --

I'm experiencing a problem with an image that I'm working on that I don't really know the most efficient way to solve. In the sample image, you'll see the metal panels in the lower right corner have a considerable amount of noise on them -- I'm assuming from GI processing. But I have the settings set to vray's high preset already. As it stands now, just this crop of the rendering takes 40 minutes distributed on four machines to render out, so it's quite a rendering hit for some pretty distorted shadows.



Anyone have any ideas? The metal material that's in shadow has diffused vray reflections on it -- they really pop in the sunlight, but here you can't really tell. Don't know if the added reflections are dragging it down. Anyway, here are my settings:



Thanks for your help!

Shaun[/img]

[natty]

hi
you need to raise the HSph and the Interp samples to more like 50, 50.
put the settings on medium

[Biohazard]

Natty is right concerning refining your solution.
I'll add my 2 cents :

It's useless to set so much secondary bounces depths, because they are fading to the inverse square root in the distance. 2 or 3 depths may fit almost every needs.
And if you want to avoid noise, get rid of secondary bounces. You'll be astonished by the result (for "not too complex / far from the sun" geometries).
Ok, there are cases like Sponza where you need many bounces...

Do not randomize samples (Advanced irradiance map). There's noise inside.

Use another filter than blend (blackman or catmull for edge ehancement is better)... But there is nothing to do with your noise concern. I've noticed that your AA sampler was high (-2/2) but I guess you've got sharp edges everywhere with this building...

You did not shown you QMC sampler settings. I assume your set to the maximum quality. It's risky to lower these settings because the noise generated might be heavy.

Cheers...

[flipside]

Do you use interpolation for the glossy reflections? I think your problems is there and not in the GI solution.

Min/max=-3,0 is way too high for such large resolution images, there's a very recent thread about this.

Hsph subdivs should indeed be at least 50, but also lower the min max otherwise your render will take even longer!

[ShaunDon]

Thanks for all your recommendations, guys. I've done a couple images with vray, but obviously I haven't a clue what most of these settings really mean. I've been reading the manual along with your suggestions.

I'm working on the animation portion of the job today, but I'll keep playing with the results and get back. Flipside -- I think you're probably onto something with it being the material, since it only seems to be with that metal panel material that I'm seeing really splotchy results. Here's his reflection map:



Thanks again for your help, guys.

Shaun

[flipside]

Give those metal panels a simple white vray material to try it out so you can see if it's the mat or the GI settings. I seems you don't use interpolation on the glossies (I don't know if the vraymap has this option?) so it's weird that your noise looks like that. Did you alter that cutoff thresh? The noise I would expect from glossy reflections with low subdivs looks very different than the noise you're experiencing (it should look more like noise filter of photoshop)

So I'm not sure anymore what's going on there...