Smudginess in Interactive Renders

[manishpaul_simon]

Hi,

I'm facing smudginess issues when trying to run the interactive render for my kichen render.
I have used default settings and used Nvidia AI as well. But I still face this problem. Can someone please help me out?

I tried both RTX & CUDA modes but the result is the same. And it's only part of the render where the smudginess happens.
I have attached the sketchup file for you to have a look.

https://drive.google.com/file/d/1xEA...ew?usp=sharing

Looking forward to your response on this.

Thanks

[manishpaul_simon]

Ok, I did some tinkering today. And I figured out a possible solution.

The reason for more smudginess was because my lightmix values were really high.

So what I did was increase the Camera EV slider to 10 and make the overall scene brighter.

And I only used very minimal values in the light mix to boost certain lights.


So essentially we need to adjust the camera settings first before adjusting the light mix settings.

[manishpaul_simon]

Another finding:

I found that the smudginess happens more when I use only a domelight to light up my scene.

The smudginess is less in a Sunlight+Enviornment light setup.

[konstantin_chaos]

Hi manishpaul_simon ,

I'm not 100% sure what you mean with smudginess.

Ok, I did some tinkering today. And I figured out a possible solution.
The reason for more smudginess was because my lightmix values were really high.
So what I did was increase the Camera EV slider to 10 and make the overall scene brighter.

This finding makes sense actually.
V-Ray has some internal optimizations in place to avoid excessive sampling in areas where it's not needed.
And dark areas in your image fall into that category.
So basically if your entire image is dark and you only rely on the Light Mix to brighten it V-Ray might sample less than necessary.
The same logic applies to over-bright images too. If your image is over-bright and you make it darker with Light Mix chances are you're sampling more than necessary and you render times are longer.
That is why it's always a good idea to render with balanced lighting even when Light Mix is gonna be used in the VFB.

I found that the smudginess happens more when I use only a domelight to light up my scene.
The smudginess is less in a Sunlight+Enviornment light setup.

This enforces the idea that the 'smudginess' is caused by excessive noise and insufficient sampling.
In general the Dome light needs more sampling in most situations compared to a simple Sun and Sky setup.
This is especially true when there is a sun disk in the dome texture.

Please share the Dome texture that you've used in your scene and some example images if you want me to test further.

Hope the information here helps,
Konstantin

[manishpaul_simon]

Hi Konstantin,
Thanks for your response. The dome texture that I used was from chaos cosmos, Day 26 to be precise. You can test it out with my scene which I've shared above and let me know how you were able to avoid the smudge issue in the dark areas. My guess is that I need to add some artificial lights (spherical light) close to the cabinet areas. But I would also like to maintain a neat lighting system in the scene without having to white wash the scene with excessive light.