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Noise in render

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Island
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I have a still render that has noise, particularly in the area of a texture that has normal map, but also in reflected areas. I would like to animate the file, but before doing so, I need to fix the noise. The still is rendered as an 8 bit 2500x2000 Tiff with gamma 2.2. It takes about an hour and a half on a Imac 2017 and it has more grain than I would like (see attachment). How would I improve this without significantly increasing render time?

My current Mantra render settings are:
Mantra tile size 48
Reflection limit 4
Refraction limit 4
Diffuse limit 0
Color limit 3
Ray tracing Bias 0.001
Sampling pixel sample 5x5
Gamma 2.2
Min ray samples 2
max ray samples 8
noise level 0.001
Global quality 2
Diffuse quality 1
Dicing shading multiplier 2

Attachments:
LaparoscopicKnotD1.jpg (262.8 KB)

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anon_user_40689665
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probably the shader, will need to see a hipfile…
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jsmack
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It looks like aliasing to me. How is the pattern derived? If it's a texture map you can try different filtering modes.
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Island
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hmmm. I'm using the default guassian filter for the texture. Here is the hip file and shader.
Edited by Island - Aug. 27, 2019 20:19:12

Attachments:
cyan_rope_Base_Color.png (601.8 KB)
cyan_rope_Metallic.png (222.2 KB)
cyan_rope_Normal.png (1.4 MB)
cyan_rope_Roughness.png (167.0 KB)
LaparoscopicKnotD1.hiplc (6.8 MB)

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anon_user_40689665
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yep its the shader, try this:
unlock principled shader core,
go through all the nodes and switch any specular model from GGX to Phong,
go back up to shader params and disable sheen.

…or use more specific custom shaders, you should be able to shave at-least 20% off the render-time.
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Island
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Thank you. Those suggestions helped.
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anon_user_40689665
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also attached is a setup using custom shaders.

Attachments:
laproknot_test.zip (4.6 MB)

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Island
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Thank you for your time and expertise. I see how this renders quickly and would be a much better solution for an animation. I'll see if I can incorporate some of the ideas. I can't change the sutures to bgeo files, as they will change position with the animation. Is there an advantage of saving most of the geometry as bgeo files rather than just freezing the terminal null? More importantly, I'll have to look your modified shaders in the SHOP, but they do render fast.

Before seeing your post above, I appreciate the tip that the primary problem with my renders looks like the sheen. Just changing this to zero made things a lot better. I changed the GGX to Phong, but had to tweak the reflection settings to get a better approximation of the original GGX. That improved render time about 20%. Your shaders above are very fast.
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