How to reduce noise in this case or scene or how to reduce noise in Interior ?

[rsghosh]

Hello, 

I'm trying to create a interior scene for the first time in Arnold(MaxtoA). I have done product renderings in it but never face such problems with noise.

I have a small scene with few objects in it and only a dome light with a HDRI linked to its texture to light up the scene through a window. Chalk(no Specular) material is assigned to all objects and the render settings is little changed than default.

The problem I'm facing is to decrease the noise in white render at first.

Scene setup :

1. Skydome Light - 8k HDRI as texture, Intensity 1, Exposure 6, Sample 48(nothing else changed).

2. Physical Camera - f/8, Shutter speed 1/400s, 2000 ISO(Exposure Control Installed).

3. Render Settings - Cam AA sample 3, Diffuse sample 6 and Rays 2, Specular sample 2 and Rays 1, others 0-0, Ray Limit 5, Transparency Depth 4, Low light threshold 0.005(nothing else changed).

If I change the diffuse sample and rays or light sample or camera AA or low light threshold nothing is able to reduce the noise, even there is no change I can see in the scene.

Here is the links of the file :

3DS Max 2020 - https://drive.google.com/file/d/1__1wXp14ojUlH-yR1h-7BMou_1iZx18E/view?usp=sharing

3DS Max 2019 - https://drive.google.com/file/d/1W9EQkYAdRw8QhQ93q2Sjc7NT4s_QYWJ2/view?usp=sharing

3DS Max 2018 - https://drive.google.com/file/d/1E0bv8ESjit7m6J3tSMVoEKKNULNviwm_/view?usp=sharing

Please help me with the noise reduction.

[madsd]

Downloading your file.

Will take a look at it later today and improve the situation as well as show you how to work with the case.

[madsd]

I can't attach images to the portal, its not good.

I did a couple of tests of your scene.

2000x1300 10 minutes with GPU and Optix, no noise.

1000x700 1 minute 17 seconds, no noise, only few artifacts. I used the CPU denoiser on the rendered EXR.

We will have to wait till forum is fixed, I dont feel like linking in from outside file sharing hubs.

But, I also deleted everything from your scene except mesh.
I use default settings only slightly tweaked, and I use a skylight no portals, no area lights, no hdr.

[rsghosh]

Thanks for you reply.

I'm using 2 quad lights at the window with HDRI linked in color attribute and a little change in diffuse sample in render settings and with chalk material it took 2.5 mins in 1000x556 and I'm able to reduce 85% of noise. I didn't used any denoiser.

You said "I used the CPU denoiser on the rendered EXR". You used it as an AOV ?

[madsd]

Great, progress.

I'll try record a screencast going over your scene with a couple of workflow related tips and tricks.

Using both GPU rendering and CPU rendering.

I'll start out by loading your original archived scene and take it from there ->

You can knock out noise free interiors on this case with DOF in a handfull of seconds rendering in the viewport moving around.

[rsghosh]

WOW, that will be great help, thanks Mr. Mads Drøschler.

I'm very excited to learn those tricks and tips.

[madsd]

Finished, currently uploading the screencast.

20 minutes. showing both CPU and GPU denoiser, and how to take your mesh and camera into a clean scene and with just a few clicks solve just about any issue regarding Look-dev environment for archvis interiors and final.

[madsd · Accepted solution]

There we go.

I went to the greenhouse and fixed up some melon plants while it uploaded. Greenhouses are awesome occupation in general IMO.

[rsghosh]

Thanks a lot for the screencast, it helped me a lot about that GPU rendering and denoising scene both in GPU and CPU.

I have a few questions,

1. I never use Adaptive Sampling and Progressive Render. Is it bad practice ?

2. If I'm using such low settings and using denoiser, it will erase crisp shaders and make it flat if I'm not that wrong. So, is it worth to keep low settings and use denoise for a final interior scene rendering ?

3.  How Depth Limit in render settings works exactly ?

It will be very helpful if you guide me in this, I'm getting a clearer image from your help so far, so thanks a lot again and I'm very glad to hear about your greenhouse and melons, they are good and we really need so much green to save our planet, Forest Pack can't save us haha.

[madsd]

Just calibrate a final render with reasonable amount of noise, my very low setting example is just to show how effective the denoiser is.

You can denoise a significant amount of noise and preserve texture detail. Under hood an albedo pass is generated to help preserve details, other passes are hidden from user and used to preserve things as well.

You need to install VFB+ framebuffer for the improved workflow of rendering small tests and denoising them with the CPU. For the GPU you see it straight away.

The Optix denoiser starts out with splotches, and unclear areas, like a very low res jpg with artifacts, but no noise, as seconds go, the sharpness improves on everything. Stop when you have a nice and sharp image, if you feel something is too unsharp in terms of details, let it render some more. Again use it for look-dev as its near instant and works in the viewport, so you save much time if you change from a conventional very time consuming and dated rendering workflow around Production mode.

[madsd]

- Progressive rendering renders in passes and does not finish a CPU bucket in first visit, it visits the bucket area multiple times and gradually refines the render, much like gpu rendering work.

- Adaptive sampling can be exposed with the aa_inv_density AOV it will start out as white and dim down, if you play with the threshold value, you can see this AOV change character, you can use it to focus a bit more on hard areas than on areas that cleans up a bit faster, taking noise and sampling into consideration.

[rsghosh]

OK...I got it and I need to practice more around this.

Learned many things from you via this noise issue I had. Thanks a lot for all the tips and tricks, I really appreciate your help and hoping to get solutions from you in near future whenever I stuck again.

Thanks Mr. Mads Drøschler.

[rsghosh]

Hello,

I'm facing problems when doing GPU rendering,

1.  optix not working after enable but no errors are showing.

2. I'm not able to change any sample value except camera AA in Arnold renderer tab but ray depths are changeable.

And in CPU rendering my AO pass is totally blast out, I have changed Ambient Occlusion settings but nothing is showing the correct pass.

Your help is very much needed, please give me some tips.

[madsd]

1. You need an NVIDIA GFX card, newer date helps, newest drivers installed. And you need to be patient after you start to render, the Cache needs to be build. but once it starts, its lightning fast.

2. Sample settings are unified and simplified even further on the GPU.

3. AO, just plug it into the diffuse slot and see if you can get it going there, it works with default settings.

[rsghosh]

I have 1050Ti with graphics driver updated till today. At first optix was showing error and not render was processing. But after install the latest driver I'm able to do the GPU render but optix denoiser not working at the moment.

Ok I will check the AO pass as per your tips.

[madsd]

Remember that using "production" rendering is illegal when working, and OptiX is not designed to give you anything in the frame buffer if you render in production mode.

Use Active Shade - Always(tm) and I mean always, up till the point where you need to leave pc while rendering and stick out an image on disk, any other scenario, use Active shade. OptiX is only visible through rgba_denoise AOV in active shade mode, it is also the only mode where you can flip between different AOVs.