Exporting armature to bvh file gets wrong data

Coding Python Support
1

Hi, I just made a simple blend file, and I got all 0.000000 armature data in the output bvh file, need help.

What I did:

  1. Download and open my blend file
  2. Run this operator in the python console: bpy.ops.export_anim.bvh(filepath=“3.bvh”, frame_start=1, frame_end=50)
  3. Open 3.bvh
  4. All data are 0.00000

What am I doing wrong to export selected armature data to a bvh file?

BTW, I tested this issue both on Blender 2.82 and 2.83.

animation_box.blend (690.7 KB)