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Collada armature animation doesn't correctly import
Closed, ResolvedPublic

Description

The attached file imports correctly into 3DS Max (using OpenCOLLADA plugin) but doesn't import correctly into Blender. When playing the imported animation, the armature splits in two (top and bottom) and the top ends up shifted. About the only "odd" thing I know about this armature (I didn't make it, someone else on my team did) is that the pelvis bones are non-deforming (or so I've been told).

Details

Type
Bug

Event Timeline

If it helps at all, here is the process the rig went through:

The rig was made in Blender.
FBX export to MotionBuilder.
Animated in MotionBuilder and saved back out to FBX.
FBX import into 3DS Max.
OpenCOLLADA export from 3DS Max.

If needed I could probably provide the original blend or the intermediate fbx file.

Closed duplicate:
http://projects.blender.org/tracker/index.php?func=detail&aid=29282&group_id=9&atid=498

From the report:
"It appears the exporter is configured to expect the tranformation listed with each node under <library_visual_scenes>
to be applied to whatever animation is supplied to the node in <library_animations>.

However, this is a bug since the 1.4 spec states on page 55 that channels are used to direct and thus replace the
transformation on the node itself. In other words the existing transformation on the node in section <library_visual_scenes>
should look like the transformation of the first frame given in section <library_animations>."

Let me try to clarify the issue a bit further. The problem seems to be a difference in how Blender and Collada work. In Blender, armature animation in pose mode is always added on top of the rest pose of the bone itself, while in collada this is not the case, (I think) it is specified relative to rest pose of the parent bone.

The importer should correct for this somehow, maybe converting the animation to a matrix in the right space, and then decomposing it into scale/rotation/translate again. Currently it seems to just copy the curves as is.

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

This tracker item can still be updated with useful info and closed (removed from the page above) when fixed.

Fixed in svn by Juha Mäki-Kanto. Thanks for the report!