Noiseproblem VraySun interiorrender

[torstenmiddelkoop]

Hello!

 

I have a problem concerning the noise coming from the vray sun. It is a very simple scene lit bij a VraySun and sky. I use skylightportals (8 in total to cover the holes in the wall) as well. I just can't seem to get rid of the noise. If I raise the subdivs of the skylight portals and the VraySun subdivs to 64 (in the attachment 24 subdivs) there is no improvement. Lowering the Colorthresheld or Noisethreshold also does not help that much, there still is noise. What do I miss? All of the passes are clean from noise, except the VrayLighting pass from the Vraysun. Hopefully someone can help me with some insight. I attached my settings and regionrender

 

PS (I switched off divide shading unit hence the maybe low subdivs)

 

 

 

Thanks!

[ryannelson]

Have you tried really cranking your sun shadow subdivisions? Try 100+ and see what the affect is. Also it wouldn't hurt to bump up your max AA subdivisions too into the ~15 range, might help your sampler out and decrease your render time.

[torstenmiddelkoop]

Ryan thanks for the reply,

 

I did try what you said, shadow subdivs of the VraySun and the skylight portals both to 96 subdivs. I also cranked up the max samples to 20. But there is not even a slightest difference.

 

As you can see in the attached image, the samples are fine with max to 8. But the samples are only placed in the area's where there is no shadow. So no samples are placed in the problematic noisy area, isn't that weird?

 

Thanks,

 

Torsten

[ryannelson]

What does the reflection pass look like? if you were using brute force, i'd suggest upping your bounces to add a kick of light in the dark areas... but I'm stuck. Maybe your material subdivisions are low and are contributing to how the light is being calculated?

[Francisco Penaloza]

Did you check your geometry? There is no reason why you should have that noise in the direct light area.

Check for double faces and such. Also are you using VRay dirt in your material? Or AO in your GI?

Edited January 15, 2015 by fco3d

[torstenmiddelkoop]

Thanks for the replies,

 

The reflection pass looks clean, the only noise is see in the passes are in Vraylighting. The ceiling material has no reflection at all. I've tried using brute force, but there is no difference in result as to Irradience map (+Light cahce). All geometry is single planes, and no double faces. I'm not using any Vraydirt or AO.

 

I have found where the problem arises. In my (problem-) setup I placed 7 skylightportals in front of the openings in the wall (all instanced), this setup gives the noise in the lighting pass. When I use one single skylightportal covering all the openings there is no more noise. But I wonder if this light setup is correct and gives accurate shadows?

 

How do you guys use the skylight portals? Should I give every opening its own skylightportal, or is a large one to cover more openings better? (see attachment)

 

Regards,

 

Torsten

[ryannelson]

is it even necessary to use light portals anymore? I thought the newer versions of Vray made them unnecessary?

 

What does it look like without any?

[torstenmiddelkoop]

The shadows are better defined (less blurry) with lightportals instead of not using them.

[Marco Manunta]

i had exactly your problem and i was able to tackle it by bumping up this Subdiv and interpolation subdiv of the irradiance map. Try something like 80/60 or even 100/80, this should help you. It may not solve completely the problem by the way...

[ionutteudean]

i think you went too far with noise treshhold. try 0.01 for it and also check if using 0.01 for color treshhold also is helping. if it's no major change check also material subdivs and go for higher values.

[torstenmiddelkoop]

Hello,

 

@Marco, i gave your settings a try, but the noise is still there.

@Ionet, I also gave your tips a try, bit it did not change to much,still much noise.

 

The noise is even there on a surface with simple materials settings: 160 diffuse white, no reflection, no bump.

 

The problem are the skylight portals, if i just use one large to cover all the openings its fine, but if i give every openings its own smaller skylightportal that is when the noise arises.

[ionutteudean]

Another idea would be to increase the min subdivs from adaptive image sampler to 2-4. But that's probably not a very professional way of getting rid of the noise (for me it usually works but it also increases the render time)

[Francisco Penaloza]

can you simplify your scene and post it here for us to review, I am pretty sure is not sampling, or noise threshold, by default V Ray should render that scene clean no problems.

There has to be something else, mesh wise or other elements that create that noise. did your model was created in Max or is exported from other 3d software, can you apply a Normal modifier in top of your mesh are check that.

Also in your light setting is MIS on or off? This option sometimes create unnecessary noise.

[torstenmiddelkoop]

Thanks for the help, appreciate it.

 

Everything is modeled in max, there are no double faces. I have 50 samples on Vraysun and skylightportals. In render settings i have unchecked Divide Shading Units.

What I have so far checked and did't work is:

 

- Bumping up all the lightsubids to 100, no difference.

- Lowering Colorthreshold en Noisethrehold of the adaptive sampler.

- Raisings Max AA Samples (from 8 to 20, no difference).

- Brute force instead of I.M. + L.C., no differce.

- Better qualiaty Iradiance map + Light Cache, no result.

- Untick MIS in skylight portals, no difference.

 

The attached render I rendered with override material, just diffuse 160 white, no reflection (reflection pass is black). The problem arises when i have separate Skylightportals outside of the openings.One large one to cover al openings works fine,but shadows are less defined. The problem is there when I have instanced smaller skyportals for each opening (7 in total). This is the situation in the attached images.

[torstenmiddelkoop]

And here is the stripped scene, where also the noise occurs if I render it.

NoiseTest.zip

[Francisco Penaloza]

Well I don't know how you are rendering but here I just increased the samples in the skylights to 100 and the noise was gone.

Other thing I noticed was that your color threshold in the DMC image sampler was 0.025, that's kind of height, I would leave it at 0.01 or connected with the DMC Sampler and that's will clean the noise too, even at 50 samples.

 

Turn off you sun and render only with the skylights, and check use DMC sampler Thresh it should start cleaning the noise right away. then you can just increase the samples in the lights about 100 seems fine.

 

Different ways to solve the problem, but everything seems to work here.

[jasonstewart]

Like I posted in the other thread it is the Probabalistic lights. As soon as they are turned off the lighting pass is clean although he GI is a little low. Top half of the attached images are with it off, bottom are with it on all other settings are unchanged.

 

Hopefully they fix it soon or default it to off.

 

[torstenmiddelkoop]

Thanks Jason,

 

That is the solution, Thanks. Turning it off, or raising the amount helps getting rid of the noise :-) Maybe you can explain when you need this feature to be enabled? With lots and lots of lights?

[jasonstewart]

Yea I guess so. Last I heard they were working to make the results more predictable. If you were doing a huge office building with 100 lights or something it may help but so far all I have seen is extra noise that is hard to figure out where it is coming from.

[thanulee]

I made my own setup for ur scene with alot different numbers in samples and in contrast just for practice if u dont mind :

 

- i increased sun to 1.0 (i ve read that u should not mess up with sun value in order to be physically correct and if u wanna a photographic result u should play with ur cam settings + color mapping and post)

- changed ur cam shutter + color mapping settings

- changed all ur gi settings with 2 solutions : 1 with im + lc and 1 with bf

- changed the samples of ur light sources to correspond to the gi settings (materials should be that high too)

- removed ur portals completely (they add a bit of noise no reason, almost 0 impact to the whole image and they increase render times around 30%)

 

the result was like 40% less render time on im + lc solution with better result (much accurate gi and when u add mats u see a big difference on these diffused reflections) and almost the same time with bf solution

new exposures.zip

[thanulee]

I also attach u the same solutions with ur current exposure settings. Cheers!

old exposure.zip

[torstenmiddelkoop]

Hi Thanos,

 

Thank you for looking into the problem extensively. It does an excellent job and renders really quickly and noisefree. I have some questions concerning your settings:

 

- I see you checked the 'divide shading subdivs' . You also mention that the overall subdivs of the lights and materials should be raised.

But in my believe, if I untick 'divide shading subdivs' you need less subdivs for these paramters, as the numbers are not divided by the max samples? Just enough subdivs to clean the image from noise.

 

- You also have skyportals disabled. But if I look at the lighting pass, It misses the lighting coming from the windows on the ceiling, and the lighting on the stairs? If you enable the portal there will be light on those places as well.

 

- I see you also have changed the Irradiance settings a lot. I really need to do some study on those settings, as they are not clear to me what every parameter does. Maybe you can elaborate on that?

 

Thank you so much!

[thanulee]

Hello Torsten,

 

- The divide shading parameter makes no difference f u decide to keep it on or off. Only the numbers change so its just a matter of preference and im kinda used to work with highest numbers so i leave it on. Samplewise nothing changes.

- The overall beauty pass had no affect from the skyportals, only render times (im almost sure i did this late at night haha). However if u need to post the lighting pass in ps, go ahead and turn em on, just increase also the subdivs in my method around to 128 so they dont put work on the antialising. In fact in another project i did recently, was the first time i disabled skyportals cause i had much better results without em. If u notice that they dont mess on the openings or on gi, turn em on. However dont forget these are extra lights/noise and cause much higher render times. There is also an option in them called simple (its supposed to turned on if they are on the inside of the windows in front of curtains) try using that too if u leave em on and see the result for urself. I think it general optimises em.

- Unless ur doing animation, i would strongly recommend to go with brute force on vray 3.xx and onwards. Works alot better with capturing small details in interiors. My settings are pretty high in the irradiance map and still they cause some splotches or weird artifacts depending the scene. The methodology around it was from viscorbel in a lesson he has over interior renderings and i cant explain u every single setting right now, but u should definitely watch this. Unfortunately i havent found any very good tutorial that explains how to setup up proper irradiance map + light cache besides this one which is still not the best, just a bit more in depth than others. However as i mentioned, brute force is the way with some denoiser in post. It has slightly higher render times, but only a single option to controll ur samples, and much much better result in all cases than im + lc solution. Plus embree helps the times to be quite faster when u use brute force in vray 3.xx versions as u probably know by now.

 

I ll post u later some very helpful articles about noise and vray i ve read and i would also reccomend watch grant warwicks mastering vray. It changed completely the way i worked over sampling and material approach.

Cheers!

[torstenmiddelkoop]

Cheers Thanos!