Blender raises errors when playing animation created by chrono project

[TomMontagnon]

Steps to reproduce

• Build the project from commit 341f39c (environment details below)
• Run ./bin/demo_POST_blender
• Launch an empty project in Blender 4.4.3 (same version as mentioned by the chrono_import.py found in this commit)
• Add chrono_import.py as a Blender add-on
• Import the exported.assets.py file generated by ./bin/demo_POST_blender
• Play the animation in Blender

---

Expected behavior

• The animation plays without any errors

---

Actual behavior

• The following error is raised at each frame of the animation:

AttributeError: 'NoneType' object has no attribute 'rotation_mode'
not found asset:  shape_111242043566320
not found asset:  shape_111242043566800
not found asset:  shape_111242043707632
not found asset:  shape_111242043709088
not found asset:  shape_111242043554512
Error in bpy.app.handlers.frame_change_post[0]:
Traceback (most recent call last):
  File "/home/tom/.config/blender/4.4/scripts/addons/chrono_import.py", line 1430, in callback_post
    exec(compile(f.read(), filename, 'exec'))
  File "/home/tom/Libraries/chrono_build/bin/DEMO_OUTPUT/BLENDER/output/state00053.py", line 145, in <module>
    update_camera_coordinates(
        'camera_111242043707008',
        (-3, 5, 4),
        (-0.227872, -0.139024, 0.501921, 0.822692)
    )
  File "/home/tom/.config/blender/4.4/scripts/addons/chrono_import.py", line 1321, in update_camera_coordinates
    cameraasset.rotation_mode = 'QUATERNION'

---

Environment

• Chrono version: 9.0
• Blender version: 4.4.3
• OS: Ubuntu 24.04.1

Compilation options:

BUILD_DEMOS=On
BUILD_SHARED_LIBS=On
CH_ENABLE_MODULE_IRRLICHT=On
CH_ENABLE_MODULE_POSTPROCESS=On
CH_ENABLE_MODULE_PYTHON=On
CH_ENABLE_OPENMP=On
CH_USE_BULLET_OPENMP=On
CH_USE_EIGEN_OPENMP=On
CH_USE_SIMD=On