Noise Compression Artifact
Posted: 03 August 2022 10:06 AM   [ Ignore ]  
Total Posts:  48
Joined  2021-08-07

Trying to use a Maxon Noise as an input to the Displacement node. But, just soloing the noise node I see vertical streaks where the noise is compressed. c4d file attached.

I have tried many ideas to fix this. Changed the UVs dramatically, including matching texel density of all the islands in an external tool. Changing the values in the Phong tag. Lighting. Scaling the noise. Adding more geometry. Changing values in the Redshift Object tag. Nothing seems to affect this.

It also appears with the simpler Noise node. However, it does not seem to happen with the Standard render engine and a noise shader.

Perhaps it may occur when the viewing angle of the underlying geometry is very oblique? But, when using the full material the scale of the noise does seem to be different in these areas.

Thanks,
Greg

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BaseTowerTestForCineV.c4d.zip  (File Size: 761KB - Downloads: 12)
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Posted: 03 August 2022 01:06 PM   [ Ignore ]   [ # 1 ]  
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Hi Greg,

The Noise is set to Global (The one set to Solo), which should not provide any stretch. I have adjusted the camera view to see it a little bit more clearly. I removed the Subdivision Surface since you have Tessellation on already. Subdivision could be a reason, but I didn’t see that either.
In the RS Object tag: I have set the min length to zero to get the same forced subdivision as with the SDD.

Below are my results; the final surface is illuminated with a Dome-light containing an HDR. I find it hard to justify otherwise when the working light is the only source.

I do not see stretches in the Noise.

Sorry, I checked all the noises just in case I can’t see a problem.

All the best

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Screen Shot 2022-08-03 at 1.54.25 PM.jpgScreen Shot 2022-08-03 at 1.53.54 PM.jpg
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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004
Maxon Master Trainer, VES member

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
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Posted: 03 August 2022 02:01 PM   [ Ignore ]   [ # 2 ]  
Total Posts:  48
Joined  2021-08-07

Dr. Sassi,
Thanks for your prompt response. Here is what I see when I solo the Maxon Noise in the scene file I attached in my initial posting. Two compressed areas are between the red lines. Can you see them?

https://www.icloud.com/iclouddrive/059U4kWZcE9ciEyTmMmJi3X5g#NoiseSolo

Is this an artifact of the viewing angle of the underlying geometry, maybe? I can see that in the image you posted it does show more clearly that what I see as compressed is on a surface at a high oblique angle to the camera. Maybe this isn’t ‘compressed’ actually and would look ok when viewed more directly?

In any case, in the actual scene file, with a Redshift Sky & Sun Rig for lighting, when viewed up close there are clear lines delimiting what looks to be different surface texture. Here is an image from the full scene, with SkySun and full material. You can clearly see between the red lines the difference in surface texture. I don’t think it’s shadow. The annoying part is the clear delimiting line between the two apparently different surfaces.

https://www.icloud.com/iclouddrive/0b3tPWUHoKOjRpxlqyhKV-qjA#ActualSceneFullMat

Thanks,
Greg

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Posted: 03 August 2022 02:07 PM   [ Ignore ]   [ # 3 ]  
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Joined  2021-08-07

Here is an image with sharper lighting, but still Sky/Sun Rig. The artifact is clearly visible.

https://www.icloud.com/iclouddrive/095iKXYoMu6nKKHt3Vz5YnEiA#SharperLightingTowerBase

I have SDS off, Screen Space Adaptive UNchecked, min=0, max=3.
Greg

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Posted: 03 August 2022 02:21 PM   [ Ignore ]   [ # 4 ]  
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Joined  2021-08-07

Two more images show this is clearly an artifact caused by the viewing angle.

The Ball is a marker and one can see the artifact to its left.
https://www.icloud.com/iclouddrive/080_N2k6F3oWdP-jj2MZIXWQw#BallAtObliqueView

Here the ball is in direct line with the view plane.
https://www.icloud.com/iclouddrive/040RirwtgDj2mgfnhFMH9FJBg#BallInDirectView


I don’t think this is a valid representation of the real world. Certainly the surface texture in the real world when viewed at such an oblique angle would look different but not as much as in these images, I don’t believe, and in real life I think the demarcation would not be so stark.

Maybe time to discuss with the Redshift experts?

Greg

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Posted: 03 August 2022 02:46 PM   [ Ignore ]   [ # 5 ]  
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Hi Greg,

You are looking more tangential to the areas that you call stretched. That is an expected typical result. Rotate the camera around, as I have mentioned above and that area will no longer look stretched.

Please check with the support for further details:
https://www.maxon.net/en/support-center

Bye.

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Screen Shot 2022-08-03 at 3.41.54 PM.jpg
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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004
Maxon Master Trainer, VES member

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

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