to_mesh(..., True, calc_undeformed=True) calculates deformed anyway since de491ab #59162

Closed
opened 2018-12-11 02:40:23 +01:00 by Colby Klein · 5 comments

System Information
Operating system: Windows 10 x64
Graphics card: GTX 970

Blender Version
Broken: 2.80 de491abf99 (found via git bisect)
Worked: 2.80 38ef3d6b91

Short description of error
Due to to_mesh(..., True, calc_undeformed=True) always calculating with deformed, exports of meshes with modifiers + armatures are broken as pictured when apply modifiers option is used.

image.png

image.png

Exact steps for others to reproduce the error

  1. Export attached blend as fbx
  2. Import the fbx

alternatively

  1. Open attached blend
  2. Select mesh
  3. C.selected_objects- [x].to_mesh(C.depsgraph, True, calc_undeformed=True) in py console
  4. switch mesh data to the new data block
    hotdog.blend
**System Information** Operating system: Windows 10 x64 Graphics card: GTX 970 **Blender Version** Broken: 2.80 de491abf99 (found via git bisect) Worked: 2.80 38ef3d6b91 **Short description of error** Due to `to_mesh(..., True, calc_undeformed=True)` always calculating with deformed, exports of meshes with modifiers + armatures are broken as pictured when apply modifiers option is used. ![image.png](https://archive.blender.org/developer/F5916247/image.png) ![image.png](https://archive.blender.org/developer/F5916282/image.png) **Exact steps for others to reproduce the error** 1) Export attached blend as fbx 2) Import the fbx alternatively 1) Open attached blend 2) Select mesh 3) `C.selected_objects- [x].to_mesh(C.depsgraph, True, calc_undeformed=True)` in py console 4) switch mesh data to the new data block [hotdog.blend](https://archive.blender.org/developer/F5916321/hotdog.blend)
Author

Added subscriber: @ColbyKlein

Added subscriber: @ColbyKlein
Bastien Montagne self-assigned this 2018-12-11 11:34:51 +01:00

Thing is, FBX export never uses calc_undeformed option when generating temp mesh…

Thing is, FBX export never uses calc_undeformed option when generating temp mesh…

And this is actually expected behavior.

FBX does disable Armature modifiers when generating its export mesh, otherwise we'd get double armature effect (as shown in your example). But since 2.8 we currently only have access to a viewport depsgraph, code was not relevant anymore (ideally, we want to export Render quality modifiers, but not possible currently, so we have to disable Armature modifiers for both render and viewport).

Fix for that is trivial and incoming, I believe there is no bug actually here, just misunderstanding of what 'calc_undeformedoption does: it generates extra coordinates for every vertex, available in theundeformed_co` member of each vertex.

And this is actually expected behavior. FBX does disable Armature modifiers when generating its export mesh, otherwise we'd get double armature effect (as shown in your example). But since 2.8 we currently only have access to a viewport depsgraph, code was not relevant anymore (ideally, we want to export Render quality modifiers, but not possible currently, so we have to disable Armature modifiers for both render and viewport). Fix for that is trivial and incoming, I believe there is no bug actually here, just misunderstanding of what 'calc_undeformed` option does: it generates extra coordinates for every vertex, available in the `undeformed_co` member of each vertex.
Author

OK, that's not at all the behavior I expected but if it is indeed on purpose and setting rest position myself when exporting is how it is supposed to be done, then the bug instead is that FBX (now fixed), Collada etc are all using the API wrong and so was I.

Thanks for your time.

OK, that's not at all the behavior I expected but if it is indeed on purpose and setting rest position myself when exporting is how it is supposed to be done, then the bug instead is that FBX (now fixed), Collada etc are all using the API wrong and so was I. Thanks for your time.
Author

Changed status from 'Open' to: 'Archived'

Changed status from 'Open' to: 'Archived'
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Reference: blender/blender#59162
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