Regression: EEVEE ambient occlusion artefact with HDRI lighting at long viewing distances #120872

New Issue

Dmitry C. · 2024-04-21T12:32:27+02:00

Dmitry C. commented

2024-04-21 12:32:27 +02:00

System Information
OS: Windows 10
GPU: RTX 2080, RX 7900

Blender Version
Broken: Blender 2.93.0 - 4.1.1, 4.2.0-alpha-main-8392f69e106c
Worked: Blender 2.92.0

Short description of error
Large or far away smooth-shaded objects appear faceted if Ambient Occlusion is enabled and the world uses an HDRI or a procedural sky environment. Shading from regular lights is unaffected.

Exact steps for others to reproduce the error
Add UV-sphere with radius=32, set shade smooth. Enter the Back-Ortho view and Frame Selected. Switch to LookDev, enable AO.

Additional info
Increasing the AO distance or disabling Bent Normals on the render tab fixes the problem. In 2.92 it looked fine regardless of these settings.
I could see a change like this being intentional on concave corners, but convex meshes shouldn't have any AO at all.

EEVEE-Next appears unaffected - no faceted look - but doesn't have an obvious way to toggle AO, and the overall result looks very different from either EEVEE or Cycles currently.

Likely related to the AO refactor: 64d96f68d6ef dee94afd039d
Related issues: #89575 #96358

**System Information** OS: Windows 10 GPU: RTX 2080, RX 7900 **Blender Version** Broken: Blender 2.93.0 - 4.1.1, 4.2.0-alpha-main-8392f69e106c Worked: Blender 2.92.0 **Short description of error** Large or far away smooth-shaded objects appear faceted if Ambient Occlusion is enabled and the world uses an HDRI or a procedural sky environment. Shading from regular lights is unaffected. **Exact steps for others to reproduce the error** Add UV-sphere with radius=32, set shade smooth. Enter the Back-Ortho view and Frame Selected. Switch to LookDev, enable AO. **Additional info** Increasing the AO distance or disabling Bent Normals on the render tab fixes the problem. In 2.92 it looked fine regardless of these settings. I could see a change like this being intentional on concave corners, but convex meshes shouldn't have any AO at all. EEVEE-Next appears unaffected - no faceted look - but doesn't have an obvious way to toggle AO, and the overall result looks very different from either EEVEE or Cycles currently. Likely related to the AO refactor: [64d96f68d6ef ](https://projects.blender.org/blender/blender/commit/64d96f68d6ef) [dee94afd039d](https://projects.blender.org/blender/blender/commit/dee94afd039d) Related issues: https://projects.blender.org/blender/blender/issues/89575 https://projects.blender.org/blender/blender/issues/96358

ao.png

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ao_2.92.blend

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Dmitry C. added the

labels 2024-04-21 12:32:28 +02:00

YimingWu changed title from ~~Regression: EEVEE ambient occlusion at long distances~~ to Regression: EEVEE ambient occlusion artefact with HDRI lighting at long viewing distances

2024-04-22 05:15:19 +02:00

YimingWu commented

2024-04-22 05:24:19 +02:00

Can confirm. But the edges aren't the result of AO mixing, it's just straight up the effect of Bent Normals, which shares the same distance setting of AO.

Looks like the faceted look can appears gradually when AO distance is reduced, and the threshold is related to the viewing distance. The artefact is visible in both ortho and perspective mode.

~~The artefact is apparently not visible in rendered mode, it's only appearing in HDRI lighting in material preview.~~

Not sure if the bent normal distance can be separated from the AO one, since it seems that they are done in the same pass. @fclem

Can confirm. But the edges aren't the result of AO mixing, it's just straight up the effect of Bent Normals, which shares the same distance setting of AO. Looks like the faceted look can appears gradually when AO distance is reduced, and the threshold is related to the viewing distance. The artefact is visible in both ortho and perspective mode. ~~The artefact is apparently not visible in rendered mode, it's only appearing in HDRI lighting in material preview.~~ Not sure if the bent normal distance can be separated from the AO one, since it seems that they are done in the same pass. @fclem ![image](/attachments/76bda3e9-14d3-4f09-bb71-a2ca619ce085)

image.png

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YimingWu added

Module

EEVEE & Viewport

Status

Needs Info from Developers

and removed

Status

Needs Triage

labels 2024-04-22 05:26:53 +02:00

Dmitry C. commented

2024-04-22 05:54:33 +02:00

The artefact is apparently not visible in rendered mode, it's only appearing in HDRI lighting in material preview.

This is incorrect, rendered (EEVEE) mode looks the same, assuming an environment is supplied. Happens both in perspective and ortho, though in perspective it depends on how zoomed-in you are, not on the camera distance.

> The artefact is apparently not visible in rendered mode, it's only appearing in HDRI lighting in material preview. This is incorrect, rendered (EEVEE) mode looks the same, assuming an environment is supplied. Happens both in perspective and ortho, though in perspective it depends on how zoomed-in you are, not on the camera distance.

rendered.png

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YimingWu commented

2024-04-22 08:23:42 +02:00

Thanks @chedap . Can confirm that when environment color is supplied with HDRI it will also show in rendered mode.

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Regression: EEVEE ambient occlusion artefact with HDRI lighting at long viewing distances #120872