Cycles HIP-RT wireframe artifacts in Ortographic view #117961

New Issue

Gabriel Radić · 2024-02-07T21:09:44+01:00

Gabriel Radić commented

2024-02-07 21:09:44 +01:00

System Information
Operating system: Windows 10 2024
Graphics card: 7900 XTX

Blender Version
Broken: 4.0
Worked: Not sure, haven't tested other versions

Description of issue:
In orthographic view, HIP-RT can produce some wireframe artifacts on meshes. Here are some examples of the issue:

Steps to reproduce:

Download the file attached below.
Render the viewport in orthographic view with HIP-RT on a compatible device and notice the wireframe artifacts.
Try again with the CPU (using Embree BVH) or HIP with HIP-RT disabled (using the BVH2 BVH) and notice how the artifacts aren't there.

**System Information** Operating system: Windows 10 2024 Graphics card: 7900 XTX **Blender Version** Broken: 4.0 Worked: Not sure, haven't tested other versions **Description of issue:** In orthographic view, HIP-RT can produce some wireframe artifacts on meshes. Here are some examples of the issue: |![image](/attachments/bc1c68e3-977c-48b2-bc08-3658eec19bd6)|![image](/attachments/a2545e6b-c786-4d43-8248-04b1112ed682)|![image](/attachments/0e59199c-11d6-4900-858d-e8db02a721c3)| |-|-|-| **Steps to reproduce:** 1. Download the file attached below. 2. Render the viewport in orthographic view with HIP-RT on a compatible device and notice the wireframe artifacts. 3. Try again with the CPU (using Embree BVH) or HIP with HIP-RT disabled (using the BVH2 BVH) and notice how the artifacts aren't there.

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Blender_File_Report_117961.blend

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Gabriel Radić added the

labels 2024-02-07 21:09:44 +01:00

Pratik Borhade commented

2024-02-08 05:42:30 +01:00

Hi, thanks for the report. Not much we would be able to do without .blend file. Could you remove other assets and only place the necessary object in the file where the shading is affected.
Does this happen in viewport of image render? Does this happen after tweaking the clip end value?

Hi, thanks for the report. Not much we would be able to do without .blend file. Could you remove other assets and only place the necessary object in the file where the shading is affected. Does this happen in viewport of image render? Does this happen after tweaking the clip end value?

Pratik Borhade added

Status

Needs Information from User

and removed

Status

Needs Triage

labels 2024-02-08 05:42:39 +01:00

Alaska commented

2024-02-08 05:57:34 +01:00

Edit: Sorry, I was typing this while Pratik was typing up their comment.

Since the scene is under NDA, is it possible for you to provide a simplified scene without any of the NDA content? Or are you able to provide instructions on reproducing this issue?

Useful information include:

What render engine are you using (Cycles or EEVEE or something else)
The exact steps to reproduce (You mention orthographic view, anything else? Like do you need to use the GPU for rendering? A specific shader?)
You mention this is a AMD issue? AMD GPU or CPU? What makes you say it's a AMD issue?

If you don't want to do either of those, you can privately share the file with me here (assuming the file is less than 2GB in size):
Edit: Removed link

Disclosure: I am a volunteer triager for Blender. I do not work at the Blender foundation. When you share the file with me, I will investigate the issue, figure out the steps to reproduce it (if I can reproduce the issue), then create a new file avoiding your NDA content and share that new file here for others to use in testing/bug fixing.

Edit: Sorry, I was typing this while Pratik was typing up their comment. --- Since the scene is under NDA, is it possible for you to provide a simplified scene without any of the NDA content? Or are you able to provide instructions on reproducing this issue? Useful information include: 1. What render engine are you using (Cycles or EEVEE or something else) 2. The exact steps to reproduce (You mention orthographic view, anything else? Like do you need to use the GPU for rendering? A specific shader?) 3. You mention this is a AMD issue? AMD GPU or CPU? What makes you say it's a AMD issue? If you don't want to do either of those, you can privately share the file with me here (assuming the file is less than 2GB in size): Edit: Removed link Disclosure: I am a volunteer triager for Blender. I do not work at the Blender foundation. When you share the file with me, I will investigate the issue, figure out the steps to reproduce it (if I can reproduce the issue), then create a new file avoiding your NDA content and share that new file here for others to use in testing/bug fixing.

Gabriel Radić commented

2024-02-08 09:39:52 +01:00

Ive managed to create a Blend file, that is NDA free. @PratikPB2123

https://1drv.ms/u/s!AhWJpHthcQCol5dxA049CR0SWLv4-A?e=ZYSeAU (For some reason it didn't let me upload here directly)

1.For Render Engine - Cycles
2. If you put Orto, and go on the top view for instance, and the mesh has some complexity in it, it shows this error.
3.Why I think its an AMD issue, as I've seen this way back with my Vega 64, around 2-3 years ago, so its more of an assumption than anything else.

But my scene could be at fault, although it was a fresh scene when I started out.

I want to note that this effect can be even see in the viewport without cycles.

Ive managed to create a Blend file, that is NDA free. @PratikPB2123 https://1drv.ms/u/s!AhWJpHthcQCol5dxA049CR0SWLv4-A?e=ZYSeAU (For some reason it didn't let me upload here directly) 1.For Render Engine - Cycles 2. If you put Orto, and go on the top view for instance, and the mesh has some complexity in it, it shows this error. 3.Why I think its an AMD issue, as I've seen this way back with my Vega 64, around 2-3 years ago, so its more of an assumption than anything else. But my scene could be at fault, although it was a fresh scene when I started out. I want to note that this effect can be even see in the viewport without cycles. ![image](/attachments/3b94dcfa-82dc-40b6-97b1-b879d39cf108)

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Gabriel Radić commented

2024-02-08 09:46:05 +01:00

To even further elaborate if I use CPU compute it has no issues again what so ever.

Pratik Borhade commented

2024-02-08 09:59:29 +01:00

Thanks. File has missing textures though. Could you pack them?: File > External Data > Pack Resources -> save .blend

Thanks. File has missing textures though. Could you pack them?: `File > External Data > Pack Resources` -> save .blend

Gabriel Radić commented

2024-02-08 10:40:25 +01:00

@PratikPB2123 The texture are not needed, the issue persists even without them.

Example in the image

It is as if the mesh wireframe is rendered for some reason.

@PratikPB2123 The texture are not needed, the issue persists even without them. ![image](/attachments/ab44a0f2-e52a-4cac-9665-60d40c076e74) Example in the image ![image](/attachments/36883aee-3bb0-45fb-a919-c72721417c25) ![image](/attachments/c7166691-9472-48fe-b67e-2a3c3dcd6c28) It is as if the mesh wireframe is rendered for some reason.

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Pratik Borhade commented

2024-02-08 12:11:58 +01:00

I want to note that this effect can be even see in the viewport without cycles.

This is due to very small clip start value.

Re. Cycles render output: Unable to confirm with NVIDIA 3050 and AMD iGPU: image

Can you check in 4.1 build: https://builder.blender.org/download/daily/

@Alaska , guess you have AMD graphics card. If so, can you check as well? 🙂

> I want to note that this effect can be even see in the viewport without cycles. This is due to very small clip start value. Re. Cycles render output: Unable to confirm with NVIDIA 3050 and AMD iGPU: [image](/attachments/13a429a7-64c6-4e1a-8dbb-ca6738722456) Can you check in 4.1 build: https://builder.blender.org/download/daily/ @Alaska , guess you have AMD graphics card. If so, can you check as well? 🙂

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Gabriel Radić commented

2024-02-08 12:19:37 +01:00

@PratikPB2123 I've added 1cm to 1000cm on the camera itself, the issue remained.

I'll download the 4.1.

@PratikPB2123 I've added 1cm to 1000cm on the camera itself, the issue remained. I'll download the 4.1.

Alaska commented

2024-02-08 12:32:08 +01:00

I ran some quick tests.

CPU Embree: No issue
BVH2 (Used by Metal, HIP, CUDA, and oneAPI): No issue.
Metal-RT (On Apple M1 Pro): No issue.
OptiX (On a RTX 4090): No issue.
HIP-RT (On a RX 7800XT): Can reproduce the issue.

It is a precision related issue (and I'm pretty sure I saw a bug report similar to this a while ago, I'll go look for it after this).

I say it's a precision related issue because the issue goes away as Clip End is reduced. But it also gets worse as Clip End is increased (and if Clip End is increased enough, other BVH options like Embree, BVH2, Metal-RT, etc, also experience the issue).

Based on this, @GabrielRadic my recommendation is to disable HIP-RT at the moment. You will get more reliably and predictable results without it.

I ran some quick tests. CPU Embree: No issue BVH2 (Used by Metal, HIP, CUDA, and oneAPI): No issue. Metal-RT (On Apple M1 Pro): No issue. OptiX (On a RTX 4090): No issue. HIP-RT (On a RX 7800XT): Can reproduce the issue. It is a precision related issue (and I'm pretty sure I saw a bug report similar to this a while ago, I'll go look for it after this). I say it's a precision related issue because the issue goes away as `Clip End` is reduced. But it also gets worse as `Clip End` is increased (and if `Clip End` is increased enough, other BVH options like Embree, BVH2, Metal-RT, etc, also experience the issue). Based on this, @GabrielRadic my recommendation is to disable HIP-RT at the moment. You will get more reliably and predictable results without it.

👍 1

Alaska added

and removed

Needs Information from User

labels 2024-02-08 12:34:33 +01:00

Gabriel Radić commented

2024-02-08 12:35:02 +01:00

4.1 Same:

4.1 Same: ![image](/attachments/50f7bbd4-8e49-418e-9109-1ff9b690db73)

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Gabriel Radić commented

2024-02-08 12:44:29 +01:00

I ran some quick tests.

CPU Embree: No issue
BVH2 (Used by Metal, HIP, CUDA, and oneAPI): No issue.
Metal-RT (On Apple M1 Pro): No issue.
OptiX (On a RTX 4090): No issue.
HIP-RT (On a RX 7800XT): Can reproduce the issue.

It is a precision related issue (and I'm pretty sure I saw a bug report similar to this a while ago, I'll go look for it after this).

I say it's a precision related issue because the issue goes away as Clip End is reduced. But it also gets worse as Clip End is increased (and if Clip End is increased enough, other BVH options like Embree, BVH2, Metal-RT, etc, also experience the issue).

Based on this, @GabrielRadic my recommendation is to disable HIP-RT at the moment. You will get more reliably and predictable results without it.

Alright, glad its not only on my end.
The issue is, that using Orto makes the clip "fix" invalid, as there is no proper depth and its always there almost. You can even see it in viewport if you look at specific angles with Orto enabled, like pressing 5 on Numpad and 7 for top view for instance.

The issue is quite wild and bring a lot of issues to people who render like this.

> I ran some quick tests. > > CPU Embree: No issue > BVH2 (Used by Metal, HIP, CUDA, and oneAPI): No issue. > Metal-RT (On Apple M1 Pro): No issue. > OptiX (On a RTX 4090): No issue. > HIP-RT (On a RX 7800XT): Can reproduce the issue. > > It is a precision related issue (and I'm pretty sure I saw a bug report similar to this a while ago, I'll go look for it after this). > > I say it's a precision related issue because the issue goes away as `Clip End` is reduced. But it also gets worse as `Clip End` is increased (and if `Clip End` is increased enough, other BVH options like Embree, BVH2, Metal-RT, etc, also experience the issue). > > Based on this, @GabrielRadic my recommendation is to disable HIP-RT at the moment. You will get more reliably and predictable results without it. Alright, glad its not only on my end. The issue is, that using Orto makes the clip "fix" invalid, as there is no proper depth and its always there almost. You can even see it in viewport if you look at specific angles with Orto enabled, like pressing 5 on Numpad and 7 for top view for instance. The issue is quite wild and bring a lot of issues to people who render like this.

Alaska commented

2024-02-08 13:04:09 +01:00

The issue is quite similar, and probably the same as #97259. But it's much worse for HIP-RT than the other BVHs.

Modifications to HIP-RT may help with this, or modifications in Cycle may help. I'm tagging @salipour for the HIP-RT side of things, and @brecht for the Cycles side of things.

The issue is quite similar, and probably the same as #97259. But it's much worse for HIP-RT than the other BVHs. Modifications to HIP-RT may help with this, or modifications in Cycle may help. I'm tagging @salipour for the HIP-RT side of things, and @brecht for the Cycles side of things.

Alaska changed title from ~~Blender 4.0 AMD Ortographic issues~~ to Cycles HIP-RT wireframe artifacts in Ortographic view

2024-02-08 13:04:42 +01:00

Brecht Van Lommel commented

2024-02-08 13:28:16 +01:00

Without having looked at the HIP-RT code for this, perhaps clipping the ray length to the top level BVH bounding box would help.

Alaska referenced this issue

2024-04-17 04:58:53 +02:00

Cycles HIP RT geometry artifacts #109415

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