Collada: export destroys mesh in some cases #35555

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Henry Lang · 2013-05-29T01:22:11+02:00

Henry Lang commented

2013-05-29 01:22:11 +02:00

%%%--- Operating System, Graphics card ---
here Win7 32 Bit, GeForce GTX 460/PCIe/SSE2/3DNOW!
But other People have the same problem

- Blender version with error, and version that worked ---

2.66a worked well. 2.67 and 2.67a have the problem

- Short description of error ---

In some cases vertices are wrong connected after collada-export.

- Steps for others to reproduce the error (preferably based on attached .blend file) ---

Example1:

Cube
second cube, scale it down, then scale y-axis a little bit up
Boolean Modifier for Cube1 with Cube2 as bool-object
You have now an cube with an hole (See the example-Object "Example_1" in blendfile)
Use "Limited Dissolve" with this cube.
Export it as collada.
Reimport the dae-file: The hole is screwed up.

Example2:

Cube
Bevel one of the Edges with some segments (4 as example)
Drag as example two of the segments inward into the cube
(helpful to do this is to switch to Transformorientation "Normal")
(See the example-Object "Example_2" in blendfile)
Export it as collada.
Reimport the dae-file: One side (here the right side) is screwed up.

%%%

%%%--- Operating System, Graphics card --- here Win7 32 Bit, GeForce GTX 460/PCIe/SSE2/3DNOW! But other People have the same problem - Blender version with error, and version that worked --- 2.66a worked well. 2.67 and 2.67a have the problem - Short description of error --- In some cases vertices are wrong connected after collada-export. - Steps for others to reproduce the error (preferably based on attached .blend file) --- Example1: ``` ``` 1. Cube 2. second cube, scale it down, then scale y-axis a little bit up 3. Boolean Modifier for Cube1 with Cube2 as bool-object 4. You have now an cube with an hole (See the example-Object "Example_1" in blendfile) 5. Use "Limited Dissolve" with this cube. 6. Export it as collada. 7. Reimport the dae-file: The hole is screwed up. Example2: ``` ``` 1. Cube 2. Bevel one of the Edges with some segments (4 as example) 3. Drag as example two of the segments inward into the cube (helpful to do this is to switch to Transformorientation "Normal") (See the example-Object "Example_2" in blendfile) 6. Export it as collada. 7. Reimport the dae-file: One side (here the right side) is screwed up. %%%

Henry Lang commented

2013-05-29 01:22:11 +02:00

Changed status to: 'Open'

Sergey Sharybin commented

2013-05-29 13:52:12 +02:00

%%%Hi Gaia! Afraid you're the only who could really easy resolve the issue. We'll really appreciate your help here :)%%%

Gaia Clary commented

2013-05-29 15:04:57 +02:00

%%%Works for me.
Please can you provide:

what exact settings do you use for exporting the objects ?
a blend file that contains the screwed up object after import.

thanks%%%

%%%Works for me. Please can you provide: - what exact settings do you use for exporting the objects ? - a blend file that contains the screwed up object after import. thanks%%%

Henry Lang commented

2013-05-29 17:33:57 +02:00

%%%The problem occurs, when in collda-export "Triangulate" is activated. See the pic in the 2nd Attachment.

When i activate the "Export for SecondLife"-Option, than the problem occurs inworld
in both cases: With and without "triangulate"-Option.

The workaround for SecondLife-Upload is at the moment:

Attach the triangulate-modifier to the object: Without APPLY.

Instead activate in the collada-export-options "Apply Modifiers".

%%%

%%%The problem occurs, when in collda-export "Triangulate" is activated. See the pic in the 2nd Attachment. ``` ``` When i activate the "Export for SecondLife"-Option, than the problem occurs inworld in both cases: With and without "triangulate"-Option. The workaround for SecondLife-Upload is at the moment: ``` ``` Attach the triangulate-modifier to the object: Without APPLY. Instead activate in the collada-export-options "Apply Modifiers". %%%

Henry Lang commented

2013-05-29 17:47:02 +02:00

%%%The internal-uploader don't work. I get errors. So i use pasteall.org:

The Blendfile:

http://www.pasteall.org/blend/21723

The oicture for collada-settings:

http://www.pasteall.org/pic/52438

%%%

%%%The internal-uploader don't work. I get errors. So i use pasteall.org: The Blendfile: http://www.pasteall.org/blend/21723 The oicture for collada-settings: http://www.pasteall.org/pic/52438 %%%

Gaia Clary commented

2013-05-29 17:50:04 +02:00

%%%The problem is in the triangulate function. Investigating...%%%

Gaia Clary commented

2013-05-30 19:52:07 +02:00

%%%Hi, Ideasman_42;

I have added a blend file which contains 2 ngons for comparison.
Both ngons behave differently:

the left object exports wrong, and shows broken triangles on re import.
the right object exports correct and can correctly be re imported.

the export/import fails only when the export option "triangulate" is checked.
When triangulate is disabled, then ngons always export/import just right.

Observations:

1.) the vertex order of both objects is different. hence the normals show in opposite direction.
2.) for the broken object, the function poly_find_ear() always returns NULL
3.) I think that the function poly_find_ear() will fail if the order of vertices in the mloop is not clockwise (or anti clockwise)
4.) right after triangulation, the resulting Mesh object already contains the wrong triangles.
5.) The problem is somewhwere in / below bc_triangulate_mesh() (in the collada module)

Further: The right object (working) has been created manually. I just created an edge loop and then filled the loop.
The left object is a copy of the OP's initial demo, but reduced to just one ngon.%%%

%%%Hi, Ideasman_42; I have added a blend file which contains 2 ngons for comparison. Both ngons behave differently: the left object exports wrong, and shows broken triangles on re import. the right object exports correct and can correctly be re imported. the export/import fails only when the export option "triangulate" is checked. When triangulate is disabled, then ngons always export/import just right. Observations: 1.) the vertex order of both objects is different. hence the normals show in opposite direction. 2.) for the broken object, the function poly_find_ear() always returns NULL 3.) I think that the function poly_find_ear() will fail if the order of vertices in the mloop is not clockwise (or anti clockwise) 4.) right after triangulation, the resulting Mesh object already contains the wrong triangles. 5.) The problem is somewhwere in / below bc_triangulate_mesh() (in the collada module) Further: The right object (working) has been created manually. I just created an edge loop and then filled the loop. The left object is a copy of the OP's initial demo, but reduced to just one ngon.%%%

Campbell Barton commented

2013-06-03 01:21:11 +02:00

%%%face normals were not calculated, added an argument to the conversion function for this and asserts so the error is much more obvious next time.

fixed r57208.%%%

%%%face normals were not calculated, added an argument to the conversion function for this and asserts so the error is much more obvious next time. fixed r57208.%%%

Campbell Barton commented

2013-06-03 01:21:12 +02:00

Changed status from 'Open' to: 'Resolved'

Campbell Barton closed this issue

2013-06-03 01:21:12 +02:00

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Collada: export destroys mesh in some cases #35555