MetalRT: Instancing objects lead to rendering errors (shading errors) #120848

New Issue

Sascha-Bucher · 2024-04-20T10:34:51+02:00

Sascha-Bucher commented

2024-04-20 10:34:51 +02:00

System Information
Operating system: macOS-14.4.1-arm64-arm-64bit 64 Bits
Graphics card: Metal API Apple M3 Max 1.2

Blender Version
Broken: version: 4.1.1, branch: blender-v4.1-release, commit date: 2024-04-15 15:11, hash: e1743a0317bc
Worked: ---

Short description of error
Objects that are integrated in addition to the Geonode objects are not rendered correctly with Cycles. They are displayed almost completely black in steps. In EEVEE it works correctly. I have not found out which node is responsible for this. I deleted one node after the other but the result remained the same. I can render other examples correctly. So the problem does not occur in general. A simplified test file is enclosed.

Exact steps for others to reproduce the error
Start render in Cycles and the result is not correct. Hide the collection with the Geonodes objects and the render is correct.

**System Information** Operating system: macOS-14.4.1-arm64-arm-64bit 64 Bits Graphics card: Metal API Apple M3 Max 1.2 **Blender Version** Broken: version: 4.1.1, branch: blender-v4.1-release, commit date: 2024-04-15 15:11, hash: `e1743a0317bc` Worked: --- **Short description of error** Objects that are integrated in addition to the Geonode objects are not rendered correctly with Cycles. They are displayed almost completely black in steps. In EEVEE it works correctly. I have not found out which node is responsible for this. I deleted one node after the other but the result remained the same. I can render other examples correctly. So the problem does not occur in general. A simplified test file is enclosed. **Exact steps for others to reproduce the error** Start render in Cycles and the result is not correct. Hide the collection with the Geonodes objects and the render is correct.

RenderErrorGeonodesPointsVolume.blend

1.2 MiB

Sascha-Bucher added the

labels 2024-04-20 10:34:52 +02:00

Alaska commented

2024-04-20 11:59:44 +02:00

It seems like you used a custom font to create letters. I do not have this font, so the letters do not appear. If I replace the font with the default Blender font and rendered the scene, then I can confirm the issue if I'm using Metal-RT on a Apple GPU (M1 Pro). If I turn off MetalRT, or use a different device (E.G. CPU), then I do not have the issue.

Turning off Motion Blur also fixed the issue. Which makes me believe it's the same issue as #117581
@Michael-Jones can you confirm whether or not these are the same issue?

I have attached a simplified file that can reproduce the issue. Simplified 120848.blend
The main aspects I can identify contributing to the issue are:

Instancing of geometry and how that works with MetalRT. I am using a Geometry node setup to instance some cubes. If I "realize instances" (using a realize instance node in the Geometry Nodes setup), the rendering issue seems to go away.
Motion blur being enabled (even if nothing has motion) and how that works with MetalRT.

@Sascha-Bucher, if you would like to render this scene in the meantime without these issues, you have a few options:

Turn off motion blur. Whether or not you can do this depends on your scene.
Or turn off MetalRT on your GPU. This can be done by:
- Selecting from the top of Blender Edit -> Preferences
- In the window that appears, select the tab on the left labeled System
- In the section titled Cycles render device, change MetalRT to Off
- It is likely that renders will now be slower (MetalRT is used to speed up rendering on M3 and newer devices), but correct.
Or use a different device (E.G. CPU) for rendering. But this will likely come with a major performance penalty.

It seems like you used a custom font to create letters. I do not have this font, so the letters do not appear. If I replace the font with the default Blender font and rendered the scene, then I can confirm the issue if I'm using Metal-RT on a Apple GPU (M1 Pro). If I turn off MetalRT, or use a different device (E.G. CPU), then I do not have the issue. Turning off Motion Blur also fixed the issue. Which makes me believe it's the same issue as #117581 @Michael-Jones can you confirm whether or not these are the same issue? I have attached a simplified file that can reproduce the issue. [Simplified 120848.blend](/attachments/85c2292d-3d5c-4055-8d63-61b7b4e4cef8) The main aspects I can identify contributing to the issue are: 1. Instancing of geometry and how that works with MetalRT. I am using a Geometry node setup to instance some cubes. If I "realize instances" (using a realize instance node in the Geometry Nodes setup), the rendering issue seems to go away. 2. Motion blur being enabled (even if nothing has motion) and how that works with MetalRT. --- @Sascha-Bucher, if you would like to render this scene in the meantime without these issues, you have a few options: - Turn off motion blur. Whether or not you can do this depends on your scene. - Or turn off MetalRT on your GPU. This can be done by: - Selecting from the top of Blender `Edit -> Preferences` - In the window that appears, select the tab on the left labeled `System` - In the section titled `Cycles render device`, change `MetalRT` to `Off` - It is likely that renders will now be slower (MetalRT is used to speed up rendering on M3 and newer devices), but correct. - Or use a different device (E.G. CPU) for rendering. But this will likely come with a major performance penalty.

Simplified 120848.blend

120 KiB

❤️ 1

Alaska added

and removed

labels 2024-04-20 12:00:10 +02:00

Alaska changed title from ~~Apple M3 Max: Incorrect render result in connection with geonodes~~ to MetalRT: Some objects are missing from some scenes with instancing

2024-04-20 12:00:53 +02:00

Sascha-Bucher commented

2024-04-21 07:55:52 +02:00

I can confirm that each of this adjustments does solve the problem:

Disabling Motion Blur
Not using the Metal graphics card

But I don't think the scaling of the objects is causing the problem. I have set the scaling factor to 1 for the normal objects and also no longer scaled the instances in the Geonodes. Nevertheless, the error is still there.

I also had a look the mentioned ticket #117581 @Michael-Jones and rendered the test file. The object "Pillow_3_Plane.002" does not disappear with my normal render settings (motion blur activated, cycles with metal...). Perhaps the problem no longer exists in 4.1.1. So it doesn't look like the same problem to me.

The new title of the ticket is somewhat misleading. The objects are all there, they are just rendered very unrecognizable.

I can confirm that each of this adjustments does solve the problem: - Disabling Motion Blur - Not using the Metal graphics card But I don't think the scaling of the objects is causing the problem. I have set the scaling factor to 1 for the normal objects and also no longer scaled the instances in the Geonodes. Nevertheless, the error is still there. I also had a look the mentioned ticket #117581 @Michael-Jones and rendered the test file. The object "Pillow_3_Plane.002" does not disappear with my normal render settings (motion blur activated, cycles with metal...). Perhaps the problem no longer exists in 4.1.1. So it doesn't look like the same problem to me. The new title of the ticket is somewhat misleading. The objects are all there, they are just rendered very unrecognizable.

Alaska commented

2024-04-21 10:54:43 +02:00

The new title of the ticket is somewhat misleading. The objects are all there, they are just rendered very unrecognizable.

I'm sorry, I renamed it based on what I observed (missing objects), and what I could understand from your report. If you believe it's misleading, feel free to update it.

I also had a look the mentioned ticket #117581. The object "Pillow_3_Plane.002" does not disappear with my normal render settings (motion blur activated, cycles with metal...). Perhaps the problem no longer exists in 4.1.1. So it doesn't look like the same problem to me.

I am still able to confirm this issue in Blender 4.2

In my experience, there is some level of randomness with both this issue and yours. Sometimes objects disappear, sometimes they're distorted, sometime only the bounding box is rendered.

> The new title of the ticket is somewhat misleading. The objects are all there, they are just rendered very unrecognizable. I'm sorry, I renamed it based on what I observed (missing objects), and what I could understand from your report. If you believe it's misleading, feel free to update it. > I also had a look the mentioned ticket `#117581`. The object "Pillow_3_Plane.002" does not disappear with my normal render settings (motion blur activated, cycles with metal...). Perhaps the problem no longer exists in 4.1.1. So it doesn't look like the same problem to me. I am still able to confirm this issue in Blender 4.2 In my experience, there is some level of randomness with both this issue and yours. Sometimes objects disappear, sometimes they're distorted, sometime only the bounding box is rendered.

Iliya Katushenock commented

2024-04-21 11:03:11 +02:00

Geometry nodes is not related here, new titel is more correct.

Sascha-Bucher commented

2024-04-22 08:11:06 +02:00

Okay, if the problem also occurs with instancing without Geonodes, I understand the hint. I haven't noticed this yet. But no objects disappear. They are all there, only the rendering (light tracing/shading) seems to be totally off. I have placed the original blue and red cubes next to each other on the simplified example file above and after 3 samples all cubes are still visible until the scene gets darker and darker. Test render enclosed.

Testrender-3-Samples.png

1.0 MiB

Sascha-Bucher closed this issue

2024-04-22 08:11:10 +02:00

Blender Bot added

and removed

labels 2024-04-22 08:11:12 +02:00

Sascha-Bucher changed title from ~~MetalRT: Some objects are missing from some scenes with instancing~~ to MetalRT: Instancing objects lead to rendering errors (shading errors)

2024-04-22 08:15:57 +02:00

Sascha-Bucher reopened this issue

2024-04-22 08:18:06 +02:00

Blender Bot added

and removed

labels 2024-04-22 08:18:09 +02:00

Pratik Borhade added

and removed

labels 2024-04-22 08:23:41 +02:00

Michael Jones (Apple) commented

2024-04-23 14:50:00 +02:00

@Alaska, we will be doing a QA pass over motion blur with MetalRT as it seems there are various issues including this one, #117581, and a couple of others that we've discovered internally.

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

MetalRT: Instancing objects lead to rendering errors (shading errors) #120848