Mesh Boolean node changes vertex indices randomly #92962

New Issue

Borek Bures · 2021-11-09T16:51:53+01:00

Borek Bures commented

2021-11-09 16:51:53 +01:00

System Information
Operating system: Windows-10-10.0.19042-SP0 64 Bits

Blender Version
Broken: version: 3.0.0 Beta, branch: master, commit date: 2021-11-08 15:56, hash: ab7214ca2e
Broken: version: 3.1.0 Alpha, branch: master, commit date: 2021-11-08 15:57, hash: e0dae0f98f
Worked: never, I think

Short description of error
If you perform an operation on the unchanged geometry created by a Mesh Boolean node from two objects with the Relative transformation, the indexes will change randomly each time.

Exact steps for others to reproduce the error
Watch the attached video.
Bug_Boolean_Indexes.mp4
Bug_Boolean_Indexes.blend

**System Information** Operating system: Windows-10-10.0.19042-SP0 64 Bits **Blender Version** Broken: version: 3.0.0 Beta, branch: master, commit date: 2021-11-08 15:56, hash: `ab7214ca2e` Broken: version: 3.1.0 Alpha, branch: master, commit date: 2021-11-08 15:57, hash: `e0dae0f98f` Worked: never, I think **Short description of error** If you perform an operation on the unchanged geometry created by a Mesh Boolean node from two objects with the Relative transformation, the indexes will change randomly each time. **Exact steps for others to reproduce the error** Watch the attached video. [Bug_Boolean_Indexes.mp4](https://archive.blender.org/developer/F11775540/Bug_Boolean_Indexes.mp4) [Bug_Boolean_Indexes.blend](https://archive.blender.org/developer/F11775542/Bug_Boolean_Indexes.blend)

Borek Bures commented

2021-11-09 16:51:53 +01:00

Added subscriber: @BorekBures

blender-admin commented

2021-11-09 16:51:53 +01:00

#90803 was marked as duplicate of this issue

Pratik Borhade commented

2021-11-10 09:45:46 +01:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2021-11-10 10:09:10 +01:00

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

Steffen Dünner commented

2021-11-10 10:11:24 +01:00

Added subscriber: @SteffenD

Hans Goudey changed title from ~~Geometry Nodes change vertex indexes randomly~~ to Mesh Boolean node changes vertex indexes randomly

2021-11-11 20:33:14 +01:00

Hans Goudey changed title from ~~Mesh Boolean node changes vertex indexes randomly~~ to Mesh Boolean node changes vertex indices randomly

2021-11-11 20:33:21 +01:00

Jacques Lucke commented

2021-11-19 10:18:59 +01:00

Added subscribers: @Calra, @howardt

Jacques Lucke commented

2021-11-19 10:24:06 +01:00

Added subscriber: @JacquesLucke

Jacques Lucke commented

2021-11-19 10:24:06 +01:00

This is most likely a threading related issue. It does not happen when I start Blender with one thread (-t 1).

This is most likely a threading related issue. It does not happen when I start Blender with one thread (`-t 1`).

Howard Trickey commented

2021-11-22 18:32:13 +01:00

Do we think it is a requirement that the indices are stable? I probably have a lot of work to do if that is the case, since when we started multithreading parts of it, I wasn't paying attention to making that the case.

Borek Bures commented

2021-11-22 20:52:40 +01:00

In #92962#1258122, @howardt wrote:
Do we think it is a requirement that the indices are stable? I probably have a lot of work to do if that is the case, since when we started multithreading parts of it, I wasn't paying attention to making that the case.

It is crucial if you want to further manipulate the mesh using nodes. If the vertices change after each operation or on a different computer, the entire geometry node design is almost unusable. Right now, it is impossible to manipulate specific vertices or render on render farms if any Geometry nodes use Boolean node.

> In #92962#1258122, @howardt wrote: > Do we think it is a requirement that the indices are stable? I probably have a lot of work to do if that is the case, since when we started multithreading parts of it, I wasn't paying attention to making that the case. It is crucial if you want to further manipulate the mesh using nodes. If the vertices change after each operation or on a different computer, the entire geometry node design is almost unusable. Right now, it is impossible to manipulate specific vertices or render on render farms if any Geometry nodes use Boolean node.

Howard Trickey commented

2021-11-22 21:32:39 +01:00

I can see that. The reason I'm asking is that this is a different view than Blender had when I first joined the project. I remember close to the first thing I did was put in the "Indices" view so that one could see vertex, edges, and face indices. At the time, Ton told me that I couldn't make that available as a universally available option because (if my memory is correct) the index numbers were internal details that shouldn't matter to users. So I had to make it a special "special for developers" option, which it remains today.

It does seem, with Geometry nodes, that we have moved far away from that view. Which, if it is the case, would argue from making the "Indices" view universally available, not hidden under a developers option. But, more importantly for this issue, would impose a new requirement on modeling tools that the indices of the results are viewable/usable by users and hence need to be repeatable.

When I get time, I'll see what I can do to make the order predictable. It will probably come at a bit of a performance and/or extra memory cost.

I can see that. The reason I'm asking is that this is a different view than Blender had when I first joined the project. I remember close to the first thing I did was put in the "Indices" view so that one could see vertex, edges, and face indices. At the time, Ton told me that I couldn't make that available as a universally available option because (if my memory is correct) the index numbers were internal details that shouldn't matter to users. So I had to make it a special "special for developers" option, which it remains today. It does seem, with Geometry nodes, that we have moved far away from that view. Which, if it is the case, would argue from making the "Indices" view universally available, not hidden under a developers option. But, more importantly for this issue, would impose a new requirement on modeling tools that the indices of the results are viewable/usable by users and hence need to be repeatable. When I get time, I'll see what I can do to make the order predictable. It will probably come at a bit of a performance and/or extra memory cost.

Howard Trickey self-assigned this 2021-11-22 21:34:50 +01:00

Raimund Klink commented

2021-11-22 23:12:54 +01:00

Added subscriber: @Raimund58