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Armature breaks object hierarchy
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Description

Blender Version
Broken: 2.79 -f7e9642da9c9-; 2.80 -11f2c65128dc-

Short description of error
Object is parented under a dummy and has armature at the same time. After export to FBX and importing back it loses the dummy as parent as object is now parented directly under the Armature.



Exact steps for others to reproduce the error

  1. create a dummy object and cube object
  2. set the dummy as parent to the cube
  3. create an Armature with a single bone
  4. for the Cube, create an Armature modifier and link it to the created armature
  5. create vertex group with the name of created bone and link all vertices to it
  6. export all into FBX, create an empty scene and import the FBX back
  7. see that the dummy is no longer parent to the Cube and Cube is now parented under the Armature

Details

Type
Bug

Event Timeline

Sebastian Parborg (zeddb) triaged this task as Incomplete priority.Thu, Jan 3, 9:56 PM

@Bastien Montagne (mont29) is this a bug or a "exporting to .fbx will make you lose this information" issue?

@Bastien Montagne (mont29) is this a bug or a "exporting to .fbx will make you lose this information" issue?

Importing of FBX is causing losing of the original parent...when I import the same FBX into Maya the dummy is still the parent

@Jan Javůrek (skywalger) could you please reproduce this in a simpler file? (with cubes mostly). As simple as possible to reproduce the issue.

There is no real way to fix this, as FBX does have a real concept of armature (it takes Maya's model roughly, using simple chains of empties [joints]). So 'strong' armature concept like Blender one has to be converted, and this will often lead to loss of info at some point. Waiting for simple file but kinda doubt there is much to be done here.

@Jan Javůrek (skywalger) could you please reproduce this in a simpler file? (with cubes mostly). As simple as possible to reproduce the issue.

There you go...one cube, parented under a dummy and skinned to a bone at the same time.



The thing is, that we (in the company) would like to use this hierarchy information for hiding of various parts of an asset in our new game engine. The FBX must be editable by Maya, Max or Blender and serves as a source file. So for example the FBX is initially created by a Blender user...later adjusted by Maya user and then again by Blender user...and here is the problem when the information gets lost.

If the problem doesn't get solved, then we have to figure out some other way (like to store the armature separately maybe so the hierarchy doesn't break), or be OK that the FBX can´t be imported into Blender.

This will be a blocker in cases when the asset must be edited by a Blender user and the .blend file is not available or not up to date with the FBX.

Bastien Montagne (mont29) raised the priority of this task from Incomplete to Normal.Fri, Jan 18, 11:42 AM