incorrect bone offset causes dae animation corruption #115969

New Issue

billconan · 2023-12-09T04:03:56+01:00

billconan commented

2023-12-09 04:03:56 +01:00

System Information
Operating system: macOS-14.1.2-arm64-arm-64bit 64 Bits
Graphics card: Metal API Apple M2 1.2

Blender Version
Broken: version: 4.0.1, branch: blender-v4.0-release, commit date: 2023-11-16 16:40, hash: d0dd92834a08
Worked: (newest version of Blender that worked as expected)

Short description of error

I have a blender file containing a character animation. The animation looks ok in blender,

but once I export it to a dae file, it becomes completely corrupted.

For example, if I import it into an empty blender scene, the animation will be stretched.

And it is even worse in MacOS' finder

Exact steps for others to reproduce the error

please see the attached blender file, try exporting the animation to a dae file. Then check the file preview in MacOS finder or reimporting it into blender.

Root cause

both the mesh and the bones have an offset. however when exporting to a dae file, blender doesn't seem to include the offset for the mesh, but does respect the offset for the bones. hence the bones and the mesh don't align anymore.

Opening the dae file in a text editor, modifying this line (removing the bone offset along the z axis)

    <bind_shape_matrix>1 0 0 0 0 1 0 0 0 0 1 -2.078348 0 0 0 1</bind_shape_matrix>

to

    <bind_shape_matrix>1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1</bind_shape_matrix>

will correct the animation.

**System Information** Operating system: macOS-14.1.2-arm64-arm-64bit 64 Bits Graphics card: Metal API Apple M2 1.2 **Blender Version** Broken: version: 4.0.1, branch: blender-v4.0-release, commit date: 2023-11-16 16:40, hash: `d0dd92834a08` Worked: (newest version of Blender that worked as expected) **Short description of error** I have a blender file containing a character animation. The animation looks ok in blender, ![Screenshot 2023-12-08 at 6.35.41 PM.png](/attachments/1c9f1796-74c4-4117-b6d9-02f15c3e99b5) but once I export it to a dae file, it becomes completely corrupted. For example, if I import it into an empty blender scene, the animation will be stretched. ![Screenshot 2023-12-08 at 6.36.17 PM.png](/attachments/560be52b-7c88-42e9-bb08-cd30d9cbf448) And it is even worse in MacOS' finder ![Screenshot 2023-12-08 at 6.36.39 PM.png](/attachments/32256861-0c64-4f9c-8452-1ae8b5a29d9d) **Exact steps for others to reproduce the error** please see the attached blender file, try exporting the animation to a dae file. Then check the file preview in MacOS finder or reimporting it into blender. **Root cause** both the mesh and the bones have an offset. however when exporting to a dae file, blender doesn't seem to include the offset for the mesh, but does respect the offset for the bones. hence the bones and the mesh don't align anymore. Opening the dae file in a text editor, modifying this line (removing the bone offset along the z axis) <bind_shape_matrix>1 0 0 0 0 1 0 0 0 0 1 -2.078348 0 0 0 1</bind_shape_matrix> to <bind_shape_matrix>1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1</bind_shape_matrix> will correct the animation.

Screenshot 2023-12-08 at 6.36.17 PM.png

346 KiB

Screenshot 2023-12-08 at 6.36.39 PM.png

51 KiB

Screenshot 2023-12-08 at 6.35.41 PM.png

138 KiB

cuberun.blend

1.3 MiB

billconan added the

Priority

Normal

Type