BMesh booleans fail with self-overlapping geometry #52425

New Issue

John Thomas · 2017-08-17T09:56:42+02:00

John Thomas commented

2017-08-17 09:56:42 +02:00

System Information
Win7, nVidia GForce 1060

Blender Version
Broken: 2.79.1 - 66c1b213 (2.78.c is broken also)
Worked: (optional)

Short description of error

In the attached Blend file we have an object named Cover from which we try to extract via Difference Boolean Modifier two objects named Cutout and Cutout 2. With BMesh the thing doesn't work (press Apply - to see faces and vertices artifacts). Choosing Carve as Boolean library it works ok.Blender-difference-bugs.blend

**System Information** Win7, nVidia GForce 1060 **Blender Version** Broken: 2.79.1 - 66c1b213 (2.78.c is broken also) Worked: (optional) **Short description of error** In the attached Blend file we have an object named *Cover* from which we try to extract via Difference Boolean Modifier two objects named *Cutout* and *Cutout 2*. With BMesh the thing doesn't work (press Apply - to see faces and vertices artifacts). Choosing Carve as Boolean library it works ok.[Blender-difference-bugs.blend](https://archive.blender.org/developer/F715196/Blender-difference-bugs.blend)

John Thomas commented

2017-08-17 09:56:42 +02:00

Changed status to: 'Open'

John Thomas commented

2017-08-17 09:56:42 +02:00

Added subscriber: @m.Th

Sebastian Koenig commented

2017-08-17 21:04:34 +02:00

Added subscriber: @sebastian_k

Sebastian Koenig commented

2017-08-17 21:04:34 +02:00

Yeah, that's true. It's weird, the meshes are also note really broken nor do they have flipped normals, so I don't see why it shouldn't work here.
I also noticed it myself that sometimes Carve works better than BMesh for no apparent reason.

Yeah, that's true. It's weird, the meshes are also note really broken nor do they have flipped normals, so I don't see why it shouldn't work here. I also noticed it myself that sometimes Carve works better than BMesh for no apparent reason.

John Thomas commented

2017-08-18 09:08:42 +02:00

"Yeahm, that's true" - to quote you. :) "...for no apparent reason" is the thing which disturbs me the most.

Look here: https://developer.blender.org/T52329

I post a very simple case to show a bug in BMesh. It was "fixed" (thaks a lot for the effort, btw) but if I move slightly one of the objects which are one of the parts of the Boolean Operator, the bug surfaces again.

Can we have something more trusty?

How other modelling programs solve this problem?

"Yeahm, that's true" - to quote you. :) "...for no apparent reason" is the thing which disturbs me the most. Look here: https://developer.blender.org/T52329 I post a very simple case to show a bug in BMesh. It was "fixed" (thaks a lot for the effort, btw) but if I move slightly one of the objects which are one of the parts of the Boolean Operator, the bug surfaces again. Can we have something more trusty? How other modelling programs solve this problem?

John Thomas commented

2017-08-18 09:10:03 +02:00

Added subscriber: @ideasman42

John Thomas commented

2017-08-18 09:10:03 +02:00

@ideasman42 , please, perhaps can you shed a light on this task and on the https://developer.blender.org/T52329 which is closely related?

TIA for your effort!

@ideasman42 , please, perhaps can you shed a light on this task and on the https://developer.blender.org/T52329 which is closely related? TIA for your effort!

Sergey Sharybin commented

2017-09-12 11:18:38 +02:00

Added subscriber: @Sergey

Campbell Barton was assigned by Sergey Sharybin

2017-09-12 11:18:38 +02:00

Sergey Sharybin commented

2017-09-12 11:18:38 +02:00

@ideasman42, afraid this one is for you ;)

Campbell Barton commented

2017-09-12 12:08:25 +02:00

There are two problems here:

The mesh has degenerate geometry (run degenerate-dissolve tool removes 96 faces)
Cover has two exactly overlapping regions (remove doubles removes 48 verts).

This could be supported, but for now you can't put objects exactly side by side and expect them to behave a solid.

There are two problems here: - The mesh has degenerate geometry (run degenerate-dissolve tool removes 96 faces) - `Cover` has two exactly overlapping regions (remove doubles removes 48 verts). This could be supported, but for now you can't put objects exactly side by side and expect them to behave a solid.

Campbell Barton changed title from ~~Difference Boolean Modifier does not work with BMesh. Works with Carve~~ to BMesh booleans fail with self-overlapping geometry

2017-09-12 12:08:58 +02:00

blender-admin commented

2020-09-07 20:26:00 +02:00

This issue was referenced by de21ab418d

This issue was referenced by de21ab418d69ca82a07ec7c836b1deca09bbd57f

Howard Trickey commented

2020-09-07 20:34:21 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Howard Trickey closed this issue

2020-09-07 20:34:21 +02:00

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BMesh booleans fail with self-overlapping geometry #52425