Maniphest T68058

Obj sequence exporting does not keep vertex index order in each file
Closed, Archived
Actions

Assigned To
Bastien Montagne (mont29)
Authored By
akira fan (akirabeta)
Aug 1 2019, 12:05 PM
Tags
  • Add-ons (Community)
Subscribers
akira fan (akirabeta)
Bastien Montagne (mont29)
June (tiancaipipi110)
Mateusz (MattChowski)
Sandro (h4570)

Description

System Information
Operating system: Windows 10
Graphics card: GTX980

Blender Version
Broken: 2.80
(example: 2.79b release)
(example: 2.80, edbf15d3c044, blender2.8, 2018-11-28, as found on the splash screen)
Worked: (optional)

Short description of error
i tried to export a mesh with simple deformation animation to obj sequence files for using with Vertex animation tool in unity, but the import result is wrong, after importing back to blender i found out the vertex order of the exported ones are different from the original one.
Exact steps for others to reproduce the error

  1. select the mesh with simple deformation animation.
  2. launch File -> Export -> Wavefront(obj)
  3. checked options: selected only, animation, apply modifiers, write materials, objects as obj objects, keep vertex order, other options are unchecked and keep path mode/forward/up as their default value
  4. export obj sequences
  5. import one of the obj back and check vertex index.

Based on the default startup or an attached .blend file (as simple as possible).

twist_mod.blend692 KBDownload

Event Timeline

akira fan (akirabeta) created this task.Aug 1 2019, 12:05 PM
Bastien Montagne (mont29) changed the task status from Unknown Status to Archived.Aug 2 2019, 12:26 PM
Bastien Montagne (mont29) claimed this task.
Bastien Montagne (mont29) added a subscriber: Bastien Montagne (mont29).

Keeping vertex orders are options in both exporting and importing side of the OBJ add-ons, if you enable it in both steps, then you'll keep your original order.

June (tiancaipipi110) added a subscriber: June (tiancaipipi110).Sep 6 2019, 10:02 AM

Enable 'keep vertex order' upon OBJ export is unable to keep original order. Could you double check.

akira fan (akirabeta) added a comment.Sep 10 2019, 3:54 AM
In T68058#770499, @June (tiancaipipi110) wrote:

Enable 'keep vertex order' upon OBJ export is unable to keep original order. Could you double check.

you need to enable "keeping vertex order" for import as well.

Mateusz (MattChowski) added a subscriber: Mateusz (MattChowski).Apr 16 2021, 3:53 PM

Hey guys, this is still an issue "you need to enable "keeping vertex order" for import as well." doesn't work because Export with vertex order doesn't work either

Sandro (h4570) added a subscriber: Sandro (h4570).Aug 6 2022, 8:47 PM

Hi, I think that I also faced this problem.

Here is my case:
https://blender.stackexchange.com/questions/271285/inconsistent-order-of-vertices-faces-in-obj-files-animation

Bastien Montagne (mont29) added a comment.Aug 8 2022, 11:14 AM

'this is still an issue' is not really helping us going further here.

  • The original file in the report does work as expected (no change in vertex order) when proper export/import options are used (just checked again just now).
  • In the file in linked post above, both OBJs have exactly the same faces definition, the only differences are in vertices definitions (coordinates and normals change, as expected):

incosistent-order-obj-anim.zip2 MBDownload

  • I also re-tried with an artificially over-twisted simple case this morning, again vertex orders remain the same (the only change in face indices are for normal values, which is totally fine and expected):

T68058.zip132 KBDownload

So we are still waiting for actual proof that keeping vertex order is not working currently.