Ambient Occlusion Shader Node breaks and Creates "vertex color" like artifacts when using a color ramp #120850

New Issue

ValyArhal · 2024-04-20T13:03:18+02:00

ValyArhal commented

2024-04-20 13:03:18 +02:00

System Information
Operating system: Windows-10-10.0.22631-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2060/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 552.22

Blender Version
Broken: version: 4.1.1, branch: blender-v4.1-release, commit date: 2024-04-15 15:11, hash: e1743a0317bc
Worked: (newest version of Blender that worked as expected)

While making a mask for a darker color using the AO node, when attempting to increase the contrast of the AO color the amount of vertex color like artifacts increased with the ramp black color value increasing

simply creating a material like the third picture on a default mesh, then turning on shade smooth will result in these artifacts, no texture mapping vector seems to change this

**System Information** Operating system: Windows-10-10.0.22631-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 2060/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 552.22 **Blender Version** Broken: version: 4.1.1, branch: blender-v4.1-release, commit date: 2024-04-15 15:11, hash: `e1743a0317bc` Worked: (newest version of Blender that worked as expected) While making a mask for a darker color using the AO node, when attempting to increase the contrast of the AO color the amount of vertex color like artifacts increased with the ramp black color value increasing simply creating a material like the third picture on a default mesh, then turning on shade smooth will result in these artifacts, no texture mapping vector seems to change this

Desktop Screenshot 2024.04.17 - 12.42.21.14.png

542 KiB

Desktop Screenshot 2024.04.17 - 11.03.06.80.png

526 KiB

Desktop Screenshot 2024.04.17 - 12.48.00.50.png

1.0 MiB

Desktop Screenshot 2024.04.17 - 12.42.21.14.png

Desktop Screenshot 2024.04.17 - 11.03.06.80.png

Desktop Screenshot 2024.04.17 - 12.48.00.50.png

ValyArhal added the

labels 2024-04-20 13:03:19 +02:00

Pratik Borhade commented

2024-04-22 08:19:12 +02:00

Hi, thanks for the report. Can confirm. Though I'm not sure what results are expected here.

ValyArhal commented

2024-04-22 10:47:08 +02:00

well the expectations were that it would behave like any other "generation" nodes like noise, meaning it's not affected by the topology density, especially that shade smooth would not be causing artifacts, that the result would also reflect what the evee engine AO looks like, but on a local (unaffected by other objects only itself) static black and white gradient, with it's current behaviour the result is equivalent to cavity, in all other softwares i can simply plug the AO shader node with a result equivalent to a baked AO map, i don't understand why this would be considered a normal result

all other "generation" nodes never relied on the topology for their gradient, i would expect a result like this if it was mapped to the object generated texture coordinates, but the result is the same regardless, the fact that shade smooth makes everything worse creating AO gradients in the middle of a flat surface and all over the model no matter what doesn't sound normal, to me it looks like the whole node is not even remotely working, this same issue i remember posting about a few years ago, i was told that it was due to the topology density being to low (calling 35k faces low density is absurd) but a while after it was reported as fixed, it was around 3.3, i don't know what happened to that

well the expectations were that it would behave like any other "generation" nodes like noise, meaning it's not affected by the topology density, especially that shade smooth would not be causing artifacts, that the result would also reflect what the evee engine AO looks like, but on a local (unaffected by other objects only itself) static black and white gradient, with it's current behaviour the result is equivalent to cavity, in all other softwares i can simply plug the AO shader node with a result equivalent to a baked AO map, i don't understand why this would be considered a normal result all other "generation" nodes never relied on the topology for their gradient, i would expect a result like this if it was mapped to the object generated texture coordinates, but the result is the same regardless, the fact that shade smooth makes everything worse creating AO gradients in the middle of a flat surface and all over the model no matter what doesn't sound normal, to me it looks like the whole node is not even remotely working, this same issue i remember posting about a few years ago, i was told that it was due to the topology density being to low (calling 35k faces low density is absurd) but a while after it was reported as fixed, it was around 3.3, i don't know what happened to that

Philipp Oeser commented

2024-04-22 15:12:20 +02:00

Is this about Eevee? Or Cycles? Or both?

ValyArhal commented

2024-04-22 15:58:20 +02:00

both i would think but it's not specifically on how it renders, it's in how it's generated, material preview and render/ viewport render display, all off them have this issue regardless of evee, evee next (tested of 4.2) or cycles

while i was attempting to gather cycles in 4.1 blender has started to hang on loading kernel, but here is the model in the first pictures

so here is viewport material preview, viewport render, evee render, for some reason i can't use cycles anymore since the last gpu driver update so i can't screen shot or render a test so but the materials is 2 nodes and any mesh seems to be having the same result

additionally i only now noticed that the option "local" for the AO node does nothing and still takes into consideration all other objects as seen that the red colored AO is being computed under the clothing even tho it's a separate object

both i would think but it's not specifically on how it renders, it's in how it's generated, material preview and render/ viewport render display, all off them have this issue regardless of evee, evee next (tested of 4.2) or cycles while i was attempting to gather cycles in 4.1 blender has started to hang on loading kernel, but here is the model in the first pictures so here is viewport material preview, viewport render, evee render, for some reason i can't use cycles anymore since the last gpu driver update so i can't screen shot or render a test so but the materials is 2 nodes and any mesh seems to be having the same result additionally i only now noticed that the option "local" for the AO node does nothing and still takes into consideration all other objects as seen that the red colored AO is being computed under the clothing even tho it's a separate object

Desktop Screenshot 2024.04.22 - 15.29.01.24.png

1.1 MiB

Desktop Screenshot 2024.04.22 - 15.48.09.88.png

2.4 MiB

AO issues.png

855 KiB