double face doesn't really become single face when merge by destination #105520

New Issue

Roni-Raihan · 2023-03-07T07:14:21+01:00

Roni-Raihan commented

2023-03-07 07:14:21 +01:00

System Information
Operating system: Windows 10
Graphics card: Nvidia GeForce 940mx

Blender Version
Broken: 3.4.1
Worked: 3.2.0

Short description of error

when there are multiple faces in the same location. then try to merge into one single face (merge by destination).it doesn't really make the face single. and resulted, face normal in viewport but the face having a black color when rendered.

Exact steps for others to reproduce the error

make 2 normal faces facing each other
put the position of the two faces in the position of the same location
select all the faces a and then merge them into one face by destination M > By distance
Then render

**System Information** Operating system: Windows 10 Graphics card: Nvidia GeForce 940mx **Blender Version** Broken: 3.4.1 Worked: 3.2.0 **Short description of error** when there are multiple faces in the same location. then try to merge into one single face (merge by destination).it doesn't really make the face single. and resulted, face normal in viewport but the face having a black color when rendered. **Exact steps for others to reproduce the error** 1. make 2 normal faces facing each other 2. put the position of the two faces in the position of the same location 3. select all the faces `a` and then merge them into one face by destination `M > By distance` 4. Then render

Roni-Raihan added the

labels 2023-03-07 07:14:21 +01:00

Pratik Borhade commented

2023-03-07 11:28:41 +01:00

Hi, thanks for the report. I'm not able to replicate this locally in 3.4, 3.6
Please upload .blend file in which the issue is visible.
Can you reproduce the issue in attached file? (just merge selected faces then switch to render view)

Hi, thanks for the report. I'm not able to replicate this locally in 3.4, 3.6 Please upload .blend file in which the issue is visible. Can you reproduce the issue in attached file? (just merge selected faces then switch to render view)

105520.blend

856 KiB

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labels 2023-03-07 11:28:49 +01:00

Roni-Raihan commented

2023-03-07 23:08:47 +01:00

I forgot to mention, this happens when rendered using the cycles render engine

this is the blend file :

untitled.blend

I added some screenshots
this is the rendering result :

this is viewport rendering :

this is in the view port of the material view :

I forgot to mention, this happens when rendered using the cycles render engine this is the blend file : [untitled.blend](/attachments/64b7ba0a-f4df-4084-a0eb-9962da8606fb) I added some screenshots this is the rendering result : ![rendered.png](/attachments/7094fe1b-e9e2-4606-85cf-8caabadbee28) this is viewport rendering : ![untitled.png](/attachments/bdf07432-0bd0-40c0-b2f8-204f29099604) this is in the view port of the material view : ![untitled2.png](/attachments/22083897-619d-41de-8060-a16931cd275a)

untitled2.png

443 KiB

untitled.blend

131 KiB

untitled.png

429 KiB

rendered.png

1.6 MiB

Pratik Borhade commented

2023-03-08 10:46:00 +01:00

Hi, thanks for the file. I can repro the similar behavior locally with your file.

Worked: 3.2.0

3.2 show render output similar to 3.4+

Still I'm not able to reproduce this from scratch. Did you merge faces of two different objects? or do they belong to same object? Is it possible to share the file before merge happens?

Hi, thanks for the file. I can repro the similar behavior locally with your file. > Worked: 3.2.0 3.2 show render output similar to 3.4+ - - - Still I'm not able to reproduce this from scratch. Did you merge faces of two different objects? or do they belong to same object? Is it possible to share the file before merge happens?

Roni-Raihan commented

2023-03-11 13:32:23 +01:00

they're different object. then combined into 1 object.
this is when the faces have not been merged by destination
untitled.blend

they're different object. then combined into 1 object. this is when the faces have not been merged by destination [untitled.blend](/attachments/41795d66-fe28-4620-bd32-157217c3f61f)

untitled.blend

135 KiB

Pratik Borhade commented

2023-03-14 05:51:14 +01:00

Hi, thanks for the file. Still unable to get the results after merging faces in edit mode.
What I've done is:

Open file
Change to edit mode
M > by distance

Hi, thanks for the file. Still unable to get the results after merging faces in edit mode. What I've done is: - Open file - Change to edit mode - `M > by distance`

Roni-Raihan commented

2023-03-15 04:51:58 +01:00

hm, I also some time ago imported a model with obj and it also spawned a double face. Does that have something to do with this?

In geometry, it says there are 4 vertices. However, it has 2 faces that use the same vertex.

hm, I also some time ago imported a model with obj and it also spawned a double face. Does that have something to do with this? In geometry, it says there are 4 vertices. However, it has 2 faces that use the same vertex.

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Pratik Borhade commented

2023-04-12 08:50:41 +02:00

Right, the file uploaded at #issuecomment-897113 shows 2 faces and 4 verts. In such case the result is expected due to overlapping faces.
But still not sure how you end up with "2 faces & 4 verts".
Did you perform the same operation M > by distance ? or do you use some add-on that provides similar operation?

Right, the file uploaded at [#issuecomment-897113](https://projects.blender.org/blender/blender/issues/105520#issuecomment-897113) shows 2 faces and 4 verts. In such case the result is expected due to overlapping faces. But still not sure how you end up with "2 faces & 4 verts". Did you perform the same operation `M > by distance` ? or do you use some add-on that provides similar operation?

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labels 2023-04-12 08:50:51 +02:00

Roni-Raihan commented

2023-04-13 11:34:00 +02:00

no addon having the same operation is used, just use M > by distance

no addon having the same operation is used, just use `M > by distance`

Philipp Oeser commented

2023-04-13 12:09:22 +02:00

Note the following fixes it

C.active_object.data.validate(verbose=True)

Also spits out


ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:698 BKE_mesh_validate_arrays: 	Polys 0 and 1 use same vertices (0
ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:700 BKE_mesh_validate_arrays: , 1
ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:700 BKE_mesh_validate_arrays: , 2
ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:700 BKE_mesh_validate_arrays: , 3
ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:702 BKE_mesh_validate_arrays: ), considering poly 1 as invalid.
ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:777 BKE_mesh_validate_arrays: 	Loop 4 is unused.
ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:777 BKE_mesh_validate_arrays: 	Loop 5 is unused.
ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:777 BKE_mesh_validate_arrays: 	Loop 6 is unused.
ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:777 BKE_mesh_validate_arrays: 	Loop 7 is unused.

Still would be good to have exact repro steps from a file (before joining I would assume)

Note the following fixes it `C.active_object.data.validate(verbose=True)` Also spits out ``` ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:698 BKE_mesh_validate_arrays: Polys 0 and 1 use same vertices (0 ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:700 BKE_mesh_validate_arrays: , 1 ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:700 BKE_mesh_validate_arrays: , 2 ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:700 BKE_mesh_validate_arrays: , 3 ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:702 BKE_mesh_validate_arrays: ), considering poly 1 as invalid. ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:777 BKE_mesh_validate_arrays: Loop 4 is unused. ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:777 BKE_mesh_validate_arrays: Loop 5 is unused. ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:777 BKE_mesh_validate_arrays: Loop 6 is unused. ERROR (bke.mesh): source/blender/blenkernel/intern/mesh_validate.cc:777 BKE_mesh_validate_arrays: Loop 7 is unused. ``` Still would be good to have exact repro steps from a file (before joining I would assume)

Roni-Raihan commented

2023-04-13 18:41:21 +02:00

I have an idea, what if when we select a face, then do m > by distance, adjacently spaced faces will be merged as well (or delete one of them) instead of just merging the verts?

I have an idea, what if when we select a face, then do `m > by distance`, adjacently spaced faces will be merged as well (or delete one of them) instead of just merging the verts?

Thomas Dinges commented

2023-05-12 15:01:36 +02:00

Any updates here?

Pratik Borhade commented

2023-05-12 15:40:47 +02:00

From @lichtwerk 's investigation, this seems a case of corrupted geometry.

Still would be good to have exact repro steps from a file

We need above info.

From @lichtwerk 's investigation, this seems a case of corrupted geometry. > Still would be good to have exact repro steps from a file We need above info.

Roni-Raihan commented

2023-05-14 13:47:29 +02:00

Recently I tried m > by distance in the latest version of blender (3.5.1). It works correctly.

Recently I tried `m > by distance` in the latest version of blender (3.5.1). It works correctly.

Pratik Borhade commented

2023-05-14 17:37:11 +02:00

Hi, will close this report if crash is no longer replicable at your end.
If problem persists, feel free to open a new report.

Note the following fixes it
C.active_object.data.validate(verbose=True)

Also, the mesh was corrupted. Unless we have exact way of generating the same object from scratch, further investigation is not possible.

Thanks again for the report!

Hi, will close this report if crash is no longer replicable at your end. If problem persists, feel free to open a new report. > Note the following fixes it `C.active_object.data.validate(verbose=True)` Also, the mesh was corrupted. Unless we have exact way of generating the same object from scratch, further investigation is not possible. Thanks again for the report!

Pratik Borhade closed this issue

2023-05-14 17:37:12 +02:00

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