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Collada Import: Visual scene node hierarchy / root not handled correctly
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Description

OS: Windows 7 64-bit
Blender: 2.6 release, also tested with r41226 (32-bit build with VC2008 Express)

To reproduce:
1. Import a skeletal COLLADA model into Blender 2.6x. Say it has a root node in the visual scene called "Root".
2. Notice the "Root" node of the model is an empty node in the Outliner view, and instead has been replaced by two nodes: "Armature" and its child "Armature.001". There should only be a single armature node called "Root".

This is reproducible with Blender's own exported DAEs as well as those from Feeling ColladaMax v3.02, even in the simplest case of a cube with a single bone, which I have attached for testing. As far as why this matters:
1.) it's incorrect to just make up arbitrary node names and leave empty nodes around the scene,
2.) it gets worse the more importing/exporting occurs - try it a few times and see what happens,
3.) some applications may depend on the nodes having certain names and being in a defined order.

I have also tested this with Blender 2.58, it does a little better by at least preserving the root node's name, but it still inserts a useless "Armature" node.

Details

Type
Bug

Event Timeline

Also attaching a .blend so you can see how it looks before exporting.

Collada bugs are not being handled well so far,

for this reason they are all being set as \'TODO\' and linked from our wiki page.

http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Import_Export#OpenCollada

Hi Ben,
Could you also attach the example dae from Feeling ColladaMax please?
I think there are both import and export issues with the blender example - export in that it creates the extra empty node, and import in not getting the correct armature name.
It would be helpful for us to see the Max generated Collada for comparison.

Hey Domino,

I think you may be right about this. Actually I tried importing a ColladaMax-exported skeletal model into Blender 2.6 and it looks better in that all the bones are under a single armature, there's no extra empty node, though the armature is still named "Armature". One thing I noticed about the ColladaMax file, the root node in the visual_scene is type JOINT instead of NODE (whereas it's a NODE in Blender exported DAEs).

I personally don't have access to 3DS Max, so I don't have a simple test case, but I will attach one of the models from our game (open source RTS called 0 A.D., so the model is CC-by-SA). It's not terribly complicated, but if you need the same test case I can try to get someone on the art team with access to 3DS Max to create one. As we use COLLADA to import models and animations in our game, we are quite interested in improving Blender support as you can imagine :)


Ben

This issue has been fixed recently (i cant recall the exact revision number).
Sidenote: The camel-1.dae example revealed another unrelated bug with
the import of UV textures. That other bug has been fixed "on the fly"
in revision 58829

Your reported issue has been fixed in SVN. Thanks for taking the
time to report!.

Gaia Clary (gaiaclary) closed this task as Resolved.Aug 2 2013, 6:08 PM