Lastes Blender versions break parenting in DEMO File - BMW scene #75069

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Grzegorz Wereszko · 2020-03-24T22:58:10+01:00

Grzegorz Wereszko commented

2020-03-24 22:58:10 +01:00

System Information
Operating system: Windows 10
Graphics card: Vega 64

Blender Version
Broken: 2.82a and 2.83 -
Worked: 2.80

Short description of error
Downloaded Blender Demo Files (https://www.blender.org/download/demo-files/)

In case of BMW_27 file (dated 2016-02-26, one of the wheels parenting is lost in current versions. See attached photo of the discrepancy.

Exact steps for others to reproduce the error
Just opened the file in different blender builds.

NOTE - in latest build 94b8166a8b - part of the wheels vanish but render OK. this also occurs in Classroom file (chairs vanish but render OK)

Should I raise separate bug report on 2.83?

**System Information** Operating system: Windows 10 Graphics card: Vega 64 **Blender Version** Broken: 2.82a and 2.83 - Worked: 2.80 **Short description of error** Downloaded Blender Demo Files (https://www.blender.org/download/demo-files/) In case of BMW_27 file (dated 2016-02-26, one of the wheels parenting is lost in current versions. See attached photo of the discrepancy.![broken parenting.png](https://archive.blender.org/developer/F8427522/broken_parenting.png) **Exact steps for others to reproduce the error** Just opened the file in different blender builds. NOTE - in latest build 94b8166a8b05 - part of the wheels vanish but render OK. this also occurs in Classroom file (chairs vanish but render OK) Should I raise separate bug report on 2.83?

Grzegorz Wereszko commented

2020-03-24 22:58:10 +01:00

Added subscriber: @Prodeous

Germano Cavalcante commented

2020-03-25 19:28:00 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-03-25 19:28:00 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Germano Cavalcante commented

2020-03-25 19:28:00 +01:00

I can confirm.
This is a problem in the Workbench, if you switch to Eevee the missing objects reappear.

I can confirm. This is a problem in the Workbench, if you switch to Eevee the missing objects reappear.

Jeroen Bakker commented

2020-03-26 11:47:27 +01:00

Added subscriber: @Jeroen-Bakker

Jeroen Bakker commented

2020-03-26 11:47:27 +01:00

I am not able to reproduce. Using classroom.blend or bmw27_cpu.blend freshly downloaded from blender.org
671b6d41c4 Linux Intel

I am not able to reproduce. Using classroom.blend or bmw27_cpu.blend freshly downloaded from blender.org 671b6d41c4 Linux Intel

Germano Cavalcante commented

2020-03-26 11:59:58 +01:00

Added subscriber: @fclem

Germano Cavalcante commented

2020-03-26 11:59:58 +01:00

Here the problem is evident:

Operating system: Windows-10-10.0.18941 64 Bits
Graphics card: Radeon (TM) RX 480 Graphics ATI Technologies Inc. 4.5.13586 Core Profile Context 19.50.01.05 26.20.15001.5006

@fclem, can you repro the problem?

Here the problem is evident: ![inst_bug.gif](https://archive.blender.org/developer/F8428572/inst_bug.gif) **Operating system:** Windows-10-10.0.18941 64 Bits **Graphics card:** Radeon (TM) RX 480 Graphics ATI Technologies Inc. 4.5.13586 Core Profile Context 19.50.01.05 26.20.15001.5006 @fclem, can you repro the problem?

Clément Foucault self-assigned this 2020-03-26 16:26:53 +01:00

Clément Foucault commented

2020-03-26 16:26:53 +01:00

I can reproduce with proprietary drivers on linux. Seems linked to instanced rendering.

Clément Foucault commented

2020-03-26 17:02:08 +01:00

This is caused by MultiDrawIndirect in conjunction with (hypothetically) reading a default non enabled attribute (which should give default color of vec4(0.0, 0.0, 0.0, 1.0)). The attrib is not even always read.

  if (materialIndex == 0) {
    color_interp = ac.rgb;
  }

My instinct tells me that the driver creates a dummy VBO for non enabled attribs but this VBO is not configured correctly when doing MDI so we get an out of bound read and undefined behavior.

This is a bug in the GL driver implementation.

This is caused by MultiDrawIndirect in conjunction with (hypothetically) reading a default non enabled attribute (which should give default color of vec4(0.0, 0.0, 0.0, 1.0)). The attrib is not even always read. ``` if (materialIndex == 0) { color_interp = ac.rgb; } ``` My instinct tells me that the driver creates a dummy VBO for non enabled attribs but this VBO is not configured correctly when doing MDI so we get an out of bound read and undefined behavior. This is a bug in the GL driver implementation.

Jeroen Bakker commented

2020-03-26 17:11:21 +01:00

@Prodeous can you upload the system-info.txt generated from blenders' Help menu to this ticket. This file contains information about the driver you are using.

Jeroen Bakker commented

2020-03-26 17:11:36 +01:00

Changed status from 'Confirmed' to: 'Needs User Info'

blender-admin commented

2020-03-26 21:10:29 +01:00

This issue was referenced by 56e0249489

This issue was referenced by 56e0249489ce89954a54d5006ddf4147dd02e208

Clément Foucault commented

2020-03-26 21:11:16 +01:00

Changed status from 'Needs User Info' to: 'Resolved'

Clément Foucault closed this issue

2020-03-26 21:11:16 +01:00

Grzegorz Wereszko commented

2020-03-26 21:44:54 +01:00

{F8429216}I used Radeon 20.3.1 drivers (latest). Note that all three version (as per origianl post) were done on the same system, so not a driver issue. eager to test that workaround when its out. but for completeness attached the requested system info file.

Another point, and the original BUG report. The "Parenting" of the wheel on the BMW27 file is broken after version 2.80. in 2.82a and latest the wheel is rotated almost 180*.. not a full 180, but definitley not as it should.

I can't replicate this with other files, but this file was pulled from blender demo files, so should be possible to replicate.

{[F8429216](https://archive.blender.org/developer/F8429216/system-info.txt)}I used Radeon 20.3.1 drivers (latest). Note that all three version (as per origianl post) were done on the same system, so not a driver issue. eager to test that workaround when its out. but for completeness attached the requested system info file. Another point, and the original BUG report. The "Parenting" of the wheel on the BMW27 file is broken after version 2.80. in 2.82a and latest the wheel is rotated almost 180*.. not a full 180, but definitley not as it should. I can't replicate this with other files, but this file was pulled from blender demo files, so should be possible to replicate.

Thomas Dinges added this to the 2.83 LTS milestone 2023-02-08 16:38:06 +01:00

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Lastes Blender versions break parenting in DEMO File - BMW scene #75069