Noise in Vray reflections

[pal1]

I have just started using Vray and I am having some trouble with the reflections in this scene. Does anyone know what might be causing the yellow noise? I have attached the render and material settings if that helps. Any help would be greatly appreciated, thank you.

[Corey Beaulieu]

The only thing that thing that I see that could be out of whack (and maybe I'm overlooking something) is that you should tick Clamp Output on in the Color Mapping. With really shiny materials, the reflection can peak and without this ticked they will create spots like you have. I would have expected it on the chrome though. Well, I guess it's a little on the chrome.

 

This would be my bet.

Edited January 11, 2013 by CoreyMBeaulieu

[Francisco Penaloza]

I tried to re create your scene but I am not getting the same problem, at first view I think it is something related to your background image, how is your lighting set up??

are you using an HDRI?

why you are using 10 bounces in your reflection depth? usually 5 is more than enough, you increase this value when you have complex transparencies and reflections situations only.

also I think Corey meant you to check Sub-pixell mapping and not clamp out.

Clamp out will limit your color spectrum to not float info, although since you are using Reinhard it actually does not mater to much because this is limiting the color info any ways.

[Corey Beaulieu]

I meant what I said. and Reinhard with a burn value of 1.0 is the same as Linear Color Mapping. Tick Clamp Output on.

 

This would still be my bet.

[CRD]

I believe the noise might be caused by an overbright tiny light. The problem is that this light is so small that it only gets hit by some of the rays being shot into the scene. If you are using a VRaySun, there is a check box to make it invisible.

[Ismael]

Supersampled

[pal1]

Thank you for all your replies.

 

Corey - I tried ticking the clamp output and tried it with different values from 0.1 to 2 and it still had the blocky corruption. The bright spots were darker though.

 

Francisco - The lighting is a vray dome light with an hdri applied to it. The same hdri map was added to the environment map in the environment and effects menu. The number of bounces was set at 10 because i was trying a few different setting and i didn't reset it back to 5. I usually use 5.

The same with the Reinhard, I have been using intensity exponential since I started using Vray. The Reinhard does limit the colours, I never noticed that before. Both Reinhard and intensity exponential had the the same yellow spots.

 

Colin - I am using an hdri applied to a Vray dome light and the sun is quite low in the sky. The sun was also behind the camera so that might have something to do with it. If I make the dome light invisble the background is darker but the objects appear the same.

 

Ismael - I tried adjusting the image sampler but I could only get a slight improvement.

 

Thank you all again for your comments

[wda]

In some cases it's a sampling issue with ray tracing. Not enough samples being taken to properly render all the lighting/reflection information to the output pixels. Blurring the HDR image in some cases, when all else fails, may help to minimize.

[enriquecuarental]

Hi everyone,

 

I have the same problem. It sounds like when vray is calculating the glossy reflections, it throws as many rays as subdivisions are set. These rays have to go too far to gather the reflection information of the environment. The farther they go the more separated they gather the lighting information from, so they get very different lighting information from the next ones. This fact produces the noise in the glossy reflections.

 

Did anyone figure out the solution?

[berez]

Paul can you show Image sampler settings? do you use DMC?

I got something similar when I used to sharp Antialiasing filter.

try tick maybe "don't affect colours" in color mapping roll-out

Edited April 9, 2013 by berez

[beestee]

Looks like under-sampled reflective caustics to me judging by the shadow direction.

[aaronrumple]

Try sub pixel sampling. I had a scene where a car had noise that wouldn't go awya with any subdivision or other settings. With subpixel sampling I could use pretty coarse settings and the issue went away.

[vinametalmetal]

Hello! Ok try to increase light subdivisions and don't use Low in irradiance, Always use medium and minimum 60 on hsph, uncheck multipass. If you usually make some tests using low values maybe you gonna have some problem on final image, bcoz the low settings cannot capture all the lights effects, so its a error use low values in some engine settings. And reflections max depth is only used to make the reflection to capture more layers. Not is necessary use 0,005 on treshold, try 0,007 its a good value and increase adaptive to 1,0, decrease only if you have a complex light effect or get more quality on micro details. And most importante, verify map coordenates and Hdri resolution in light map,On color mapping check clamp output and increase value to "tweak light overexposure", So is this, good luck!

Edited April 17, 2013 by vinametalmetal
vital information

[wendys_78]

i'm experiencing the same, look exactly like your scene, and i'm new to 3ds max also, trying to figure out your scene but don't know where to change undersampled to become supersampled, if u may give some info it will be great, i think this is the solution for my scene, thanks a lot before..

[Ismael]

http://www.fxguide.com/featured/the-state-of-rendering/