Boolean (Exact) Issue w/ overlapping geometry #85780

New Issue

Em Eckx · 2021-02-19T03:55:24+01:00

Em Eckx commented

2021-02-19 03:55:24 +01:00

System Information
Operating system: Win10
Graphics card: 3070

Blender Version
Broken: 2.93, 78116a1edc, master, 2021-02-18
Worked: I don't think it ever worked proper. But boolean issues were told to be reported here.

Exact boolean fails on the following example.

Take a cylinder and select the bottom face and flip the normal with alt + N.
Then bevel the face with ctrl + B and it will go outward.
Use another cylinder and extrude is as the gif and use it as a boolean after setting it to wire display.
The geometric result should be more broken than one would generally expect.

Attached is a blend of the gif above.

exact_report1.blend

Below is a more cleaned up file.

exact_report1_1.blend

**System Information** Operating system: Win10 Graphics card: 3070 **Blender Version** Broken: 2.93, 78116a1edc9b, master, 2021-02-18 Worked: I don't think it ever worked proper. But boolean issues were told to be reported here. Exact boolean fails on the following example. ![rrraLMUOux.gif](https://archive.blender.org/developer/F9816059/rrraLMUOux.gif) Take a cylinder and select the bottom face and flip the normal with alt + N. Then bevel the face with ctrl + B and it will go outward. Use another cylinder and extrude is as the gif and use it as a boolean after setting it to wire display. The geometric result should be more broken than one would generally expect. Attached is a blend of the gif above. [exact_report1.blend](https://archive.blender.org/developer/F9816066/exact_report1.blend) Below is a more cleaned up file. ![blender_MijJqIBM5G.png](https://archive.blender.org/developer/F9816072/blender_MijJqIBM5G.png) [exact_report1_1.blend](https://archive.blender.org/developer/F9816071/exact_report1_1.blend)

Em Eckx commented

2021-02-19 03:55:24 +01:00

Added subscriber: @masterxeon1001

Howard Trickey commented

2021-02-19 04:39:48 +01:00

Added subscriber: @howardt

Howard Trickey self-assigned this 2021-02-19 04:39:48 +01:00

Howard Trickey commented

2021-02-19 04:39:48 +01:00

I'll look at this.

Philipp Oeser commented

2021-02-19 13:21:17 +01:00

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

Howard Trickey commented

2021-02-20 17:09:55 +01:00

Changed status from 'Confirmed' to: 'Archived'

Howard Trickey closed this issue

2021-02-20 17:09:55 +01:00

Howard Trickey commented

2021-02-20 17:09:55 +01:00

As Philip said, these cases work fine, I believe, if you flip the normals of the bottoms of the cylinders with the spread-out bottoms.

Boolean is intended to work with things that represent closed volumes, for the most part. (Maybe a to-be-implemented-in-the-future mode could deal with the oft desired "just trim away" case, which is what is desired here.) Closed volumes should have manifold edges and face normals that point to the outside. Since these models do not conform to that, the fallback code comes into play, and that code too assumes that the normals at least try to indicate which side is "outside". So while the results are not great here, the input is not in the form expected for Boolean, sorry.

As Philip said, these cases work fine, I believe, if you flip the normals of the bottoms of the cylinders with the spread-out bottoms. Boolean is intended to work with things that represent closed volumes, for the most part. (Maybe a to-be-implemented-in-the-future mode could deal with the oft desired "just trim away" case, which is what is desired here.) Closed volumes should have manifold edges and face normals that point to the outside. Since these models do not conform to that, the fallback code comes into play, and that code too assumes that the normals at least try to indicate which side is "outside". So while the results are not great here, the input is not in the form expected for Boolean, sorry.

Em Eckx commented

2021-02-20 17:17:04 +01:00

no problem. Nudgery helps with the issue. Thanks for checking into it for me.
Im still figuring out the rules of Exact. Thanks for the insight!

no problem. Nudgery helps with the issue. Thanks for checking into it for me. Im still figuring out the rules of Exact. Thanks for the insight!

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Boolean (Exact) Issue w/ overlapping geometry #85780