Modeling: Boolean Modifier incorrectly merges edges and faces #115557

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opened 2023-11-29 04:14:08 +01:00 by Nathan-K · 6 comments

Nathan-K commented

2023-11-29 04:14:08 +01:00

System Information
Operating system: Windows 10
Graphics card: NVIDIA GeForce RTX 3080

Blender Version
Broken: 3.5, 4.0.1
Worked: haven't found a version that doesn't have this bug

Short description of error
Combining two watertight (manifold) shapes with the modifier Boolean Union sometimes results in faces missing and weird edges.

Because faces are missing, the merged shape is no longer manifold, which corrupts further Boolean Union and Boolean Difference modifications, since I think these both rely on an object having clear inside & outside faces, and a missing face interferes in that.

The problem faces can be highlighted by, in the Viewport Overlays, checking the 'Face Orientation" checkbox. One of the missing faces is shown (in red) in the uploaded screenshot.

Disclaimer: I don't think this is specific to the python modifier, but this is how I've been able to reliably reproduce it.

Exact steps for others to reproduce the error

I have included a .blend file that has a script in it that reproduces this problem. Go to the script tab, run the script, and you can see that the final shape 'beam1' is missing faces.

How can I reliably Boolean-Union and Boolean-Difference without the edges and faces getting glitched out?

**System Information** Operating system: Windows 10 Graphics card: NVIDIA GeForce RTX 3080 **Blender Version** Broken: 3.5, 4.0.1 Worked: haven't found a version that doesn't have this bug **Short description of error** Combining two watertight (manifold) shapes with the modifier Boolean Union sometimes results in faces missing and weird edges. Because faces are missing, the merged shape is no longer manifold, which corrupts further Boolean Union and Boolean Difference modifications, since I think these both rely on an object having clear inside & outside faces, and a missing face interferes in that. The problem faces can be highlighted by, in the Viewport Overlays, checking the 'Face Orientation" checkbox. One of the missing faces is shown (in red) in the uploaded screenshot. Disclaimer: I don't think this is specific to the python modifier, but this is how I've been able to reliably reproduce it. **Exact steps for others to reproduce the error** I have included a .blend file that has a script in it that reproduces this problem. Go to the script tab, run the script, and you can see that the final shape 'beam1' is missing faces. How can I reliably Boolean-Union and Boolean-Difference without the edges and faces getting glitched out?

20231128 Merge Bug2.blend

1.1 MiB

Screenshot 2023-11-28 22.01.52.png

755 KiB

Screenshot 2023-11-28 22.01.52.png

Nathan-K added the

labels 2023-11-29 04:14:09 +01:00

Iliya Katushenock commented

2023-11-29 14:27:16 +01:00

Member

Hi, thanks for report, can you simplify report and delete add-on point? Pretty sure you can reproduce this by manually modifier applying.

Hi, thanks for report, can you simplify report and delete add-on point? Pretty sure you can reproduce this by manually modifier applying.

Germano Cavalcante added

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and removed

labels 2023-11-29 18:24:15 +01:00

Nathan-K commented

2023-11-30 02:06:23 +01:00

Author

I have simplified the report.

I have simplified the report.

Nathan-K commented

2023-12-01 00:57:47 +01:00

Author

I've provided the information requested, but I don't seem to have the ability to change the status label back to "Needs Triage"?

I've provided the information requested, but I don't seem to have the ability to change the status label back to "Needs Triage"?

Nathan-K commented

2023-12-01 02:18:44 +01:00

Author

@mod_moder I don't seem to be able to remove the 'status needs information from user' label to get this issue back in the working queue.

@mod_moder I don't seem to be able to remove the 'status needs information from user' label to get this issue back in the working queue.

Iliya Katushenock added

and removed

Needs Information from User

labels 2023-12-01 08:54:49 +01:00

Iliya Katushenock changed title from ~~blender 3 & 4 python modifier Boolean Union incorrectly merges edges and faces~~ to Modeling: Boolean Modifier incorrectly merges edges and faces

2023-12-01 08:55:15 +01:00

Philipp Oeser commented

2024-01-02 10:50:58 +01:00

Member

I can confirm the behavior.

As for workarounds:

run Mesh > Cleanup > Fill Holes followed by Face > Tris to Quads afterwards
alternatively : use the Fast method in the Boolean modifier with 0m Overlap Threshold (might require Mesh > Cleanup > Merge By Distance afterwards

Will confirm for now though

I can confirm the behavior. As for workarounds: - run `Mesh` > `Cleanup` > `Fill Holes` followed by `Face` > `Tris to Quads` afterwards - alternatively : use the `Fast` method in the Boolean modifier with 0m `Overlap Threshold` (might require `Mesh` > `Cleanup` > `Merge By Distance` afterwards Will confirm for now though

Philipp Oeser added

and removed

labels 2024-01-02 10:51:21 +01:00

Nathan-K commented

2024-01-09 02:03:51 +01:00

Author

Thanks for providing the workarounds. I've updated the script in that example blender file, and so far it seems to handle the missing spots. I'm going to use it more to see if other kinds of geometry still causes problems.

For reference, this is my updated merge function:

def merge( objs, inplace=True, name='merged_object' ) :
    obj0 = objs[0]
    if not inplace :
        obj0 = simple_copy( obj0, name=name )
    with bpy.context.temp_override( object=obj0 ) :
        for obj in objs[1:] :
            mod = obj0.modifiers.new('Boolean', type='BOOLEAN' )
            mod.operation = 'UNION'
            mod.object = obj
            bpy.ops.object.modifier_apply(modifier=mod.name)
    
    bpy.context.view_layer.objects.active = obj0
    bpy.ops.object.mode_set(mode='EDIT')
    bpy.ops.mesh.fill_holes()
    bpy.ops.mesh.tris_convert_to_quads()
    bpy.ops.object.editmode_toggle()
    
    if not inplace :
        return obj0

Thanks for providing the workarounds. I've updated the script in that example blender file, and so far it seems to handle the missing spots. I'm going to use it more to see if other kinds of geometry still causes problems. For reference, this is my updated merge function: ```Py def merge( objs, inplace=True, name='merged_object' ) : obj0 = objs[0] if not inplace : obj0 = simple_copy( obj0, name=name ) with bpy.context.temp_override( object=obj0 ) : for obj in objs[1:] : mod = obj0.modifiers.new('Boolean', type='BOOLEAN' ) mod.operation = 'UNION' mod.object = obj bpy.ops.object.modifier_apply(modifier=mod.name) bpy.context.view_layer.objects.active = obj0 bpy.ops.object.mode_set(mode='EDIT') bpy.ops.mesh.fill_holes() bpy.ops.mesh.tris_convert_to_quads() bpy.ops.object.editmode_toggle() if not inplace : return obj0 ```

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