Problem with quickeffect cell fracture #85632

New Issue

Ivan Ćosić · 2021-02-14T17:59:05+01:00

Ivan Ćosić commented

2021-02-14 17:59:05 +01:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.90

Blender Version
Broken: version: 2.91.2, branch: master, commit date: 2021-01-19 16:15, hash: 5be9ef4177
Worked: (newest version of Blender that worked as expected)

Short description of error
If I do a quickeffect cell fracture with Suzana (monkey) something is not working properly. As far as I can see, it works properly with other objects, but I have problems with it. Look at the picture?

Exact steps for others to reproduce the error
[Please describe the exact steps needed to reproduce the issue]
[Based on the default startup or an attached .blend file (as simple as possible)]

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.90 **Blender Version** Broken: version: 2.91.2, branch: master, commit date: 2021-01-19 16:15, hash: `5be9ef4177` Worked: (newest version of Blender that worked as expected) **Short description of error** If I do a quickeffect cell fracture with Suzana (monkey) something is not working properly. As far as I can see, it works properly with other objects, but I have problems with it. Look at the picture? **Exact steps for others to reproduce the error** [Please describe the exact steps needed to reproduce the issue] [Based on the default startup or an attached .blend file (as simple as possible)] ![image.png](https://archive.blender.org/developer/F9801298/image.png)

Ivan Ćosić commented

2021-02-14 17:59:05 +01:00

Added subscriber: @PredatorHall

Philipp Oeser commented

2021-02-17 15:49:10 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-02-17 15:49:10 +01:00

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

Philipp Oeser closed this issue

2021-02-17 15:49:10 +01:00

Philipp Oeser commented

2021-02-17 15:49:10 +01:00

This is because Suzanne is a non-manifold mesh (it has holes where the eyes are)
https://docs.blender.org/manual/en/latest/glossary/index.html#term-Non-manifold

The boolean modifier which is used internally does not like these
https://docs.blender.org/manual/en/latest/modeling/modifiers/generate/booleans.html

So this is not nice, but expected, it is a documentated limitation of the current system.
Think we have to close this, but thx reporting anyways!

This is because Suzanne is a non-manifold mesh (it has holes where the eyes are) https://docs.blender.org/manual/en/latest/glossary/index.html#term-Non-manifold The boolean modifier which is used internally does not like these https://docs.blender.org/manual/en/latest/modeling/modifiers/generate/booleans.html So this is not nice, but expected, it is a documentated limitation of the current system. Think we have to close this, but thx reporting anyways!

Ramil Roosileht commented

2021-03-06 16:13:10 +01:00

Added subscribers: @howardt, @Limarest

Ramil Roosileht commented

2021-03-06 16:13:10 +01:00

The actual reason why Cell Fracture fails since 2.91 is because of the Exact boolean mode set by default. In the attached video you can see that if I enable debug boolean checkbox and manually set the boolean type back to fast, pieces behave as they should. Can we reopen this bug @lichtwerk and maybe ask @howardt to look into it? QmN0HnMYPT.mp4

Exact steps to repro:

Add Suzanne
Choose Cell Fracture
Enable debug boolean so that boolean modifier would not apply automatically
Choose failed boolean piece and change boolean type from exact to fast

The actual reason why Cell Fracture fails since 2.91 is because of the Exact boolean mode set by default. In the attached video you can see that if I enable debug boolean checkbox and manually set the boolean type back to fast, pieces behave as they should. Can we reopen this bug @lichtwerk and maybe ask @howardt to look into it? [QmN0HnMYPT.mp4](https://archive.blender.org/developer/F9873348/QmN0HnMYPT.mp4) Exact steps to repro: 1. Add Suzanne 2. Choose Cell Fracture 3. Enable debug boolean so that boolean modifier would not apply automatically 4. Choose failed boolean piece and change boolean type from exact to fast

Philipp Oeser commented

2021-03-06 17:14:12 +01:00

Seems like a design choice (rather than a bug) to me.

If the Exact method is generally of better quality, then there could be situations were Cell Fracture actually improved compared to pre 2.91?
or can we be sure that Cell Fracture will always benefit from having it set to Fast?

Seems like a design choice (rather than a bug) to me. - If the `Exact` method is generally of better quality, then there could be situations were Cell Fracture actually improved compared to pre 2.91? - or can we be sure that Cell Fracture will always benefit from having it set to `Fast`?

Howard Trickey commented

2021-03-06 22:25:31 +01:00

I am looking at this. I think the new method I am using to decide inside/outside could use some tweaking. There are cases where the Fast's inside/outside test will fail on a boolean like Cell Fracture, though clearly this isn't one of them.

blender-admin commented

2021-03-07 14:54:21 +01:00

This issue was referenced by b30f89918e

This issue was referenced by b30f89918ee16ae3473faa2cfaa5c843b012d878

Howard Trickey commented

2021-03-07 14:57:45 +01:00

Changed status from 'Archived' to: 'Resolved'

Howard Trickey commented

2021-03-07 14:59:39 +01:00

I tweaked the threshold used to decide "insideness" when meshes are non-manifold and the operation is Intersect. It now works in the Suzanne case.

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Problem with quickeffect cell fracture #85632