| { |
| "id": "single-software-execution--cli--blender--task-21--ubuntu", |
| "snapshot": "Blender-4.2.3", |
| "instruction": "BVH Retarget + Bake to Action `/home/user/Desktop/character.blend` contains an armature object named `Character` with bones `Root` -> `Spine` -> `Head` (connected, all along +Z). `/home/user/Desktop/walk.bvh` is a 60-frame walk cycle whose hierarchy is `Hips` -> `Spine` -> `Head` (`Hips` has 6 channels: X/Y/Z position + Z/X/Y rotation; `Spine` and `Head` have 3 rotation channels each). Launch Blender by running `blender` from a terminal. For the steps below, use `/opt/blender/blender` for Blender command-line or background runs when working on `character.blend`.\n\nThe scene frame range is 1..60 in character.blend. retarget the BVH motion onto the `Character` rig, bake it to an Action on `Character`, strip the BVH import-artifact armature, and save the result as `/home/user/Desktop/answer.blend`. ## Mapping table Use this explicit bone-name mapping when copying fcurves from the BVH action to the character's action: source (BVH) target (Character) ----------- ------------------- Hips -> Root Spine -> Spine Head -> Head The hip translation (the `Hips` bone's `location` channels in the BVH action) must be copied onto the `Root` pose bone so the character physically walks forward. ## Requirements 1. Use the initial character scene at `/home/user/Desktop/character.blend`. 2. Import the BVH file at `/home/user/Desktop/walk.bvh` with `bpy.ops.import_anim.bvh(filepath=..., axis_forward='Y', axis_up='Z')`. The importer will create a new armature object (Blender names it after the BVH file, i.e. `walk`) with its own Action, also named `walk`. 3. Create (or reuse) an Action on the `Character` armature's `animation_data`. For every target bone in the mapping table, copy the corresponding source bone's `rotation_euler` fcurves from the BVH action; for `Root`, additionally copy the BVH `Hips` `location` fcurves. Preserve the original keyframes and handles. 4. With `Character` active and in POSE mode, call `bpy.ops.nla.bake(frame_start=1, frame_end=60, step=1, visual_keying=True, clear_constraints=True, bake_types={'POSE'}, use_current_action=True)` so the retargeted channels become a clean baked Action. 5. Delete the BVH import-artifact armature (`bpy.data.objects.remove(bvh_arm, do_unlink=True)`), its armature data-block, and the BVH-only Action if nothing else uses it. 6. Save to `/home/user/Desktop/answer.blend`. ## Requirements 1. The saved file opens as a valid Blender file. 2. The `Character` armature object still exists with armature data and bones `Root`, `Spine`, `Head`. 3. No BVH import-artifact armature remains (no armature named starting with `walk`, `bvh`, `mixamo`, and no non-Character armature whose bones include any of `Hips`, `Spine`, `Head`). 4. `Character.animation_data.action` exists with at least 30 keyframes summed across its fcurves. 5. With the scene evaluated at `frame_start` vs. `frame_end`, the world-space head position of the `Root` pose bone differs along world-Y by at least 0.5 BU (the character walked forward). 6. The baked action contains a `pose.bones[\"<target>\"].rotation_euler` fcurve for every target bone in the mapping table.", |
| "source": "https://docs.blender.org/manual/en/4.1/; https://docs.blender.org/api/4.1/; https://developer.blender.org/docs/release_notes/4.1/; https://www.loc.gov/preservation/digital/formats/fdd/fdd000507.shtml", |
| "config": [ |
| { |
| "type": "upload_file", |
| "parameters": { |
| "files": [ |
| { |
| "local_path": "task-21/init_file/character.blend", |
| "path": "/home/user/Desktop/character.blend" |
| } |
| ] |
| } |
| }, |
| { |
| "type": "upload_file", |
| "parameters": { |
| "files": [ |
| { |
| "local_path": "task-21/init_file/scene.blend", |
| "path": "/home/user/Desktop/scene.blend" |
| } |
| ] |
| } |
| }, |
| { |
| "type": "upload_file", |
| "parameters": { |
| "files": [ |
| { |
| "local_path": "task-21/init_file/walk.bvh", |
| "path": "/home/user/Desktop/walk.bvh" |
| } |
| ] |
| } |
| } |
| ], |
| "trajectory": "trajectories/", |
| "related_apps": [ |
| "blender" |
| ], |
| "artifact_paths": [ |
| "/home/user/Desktop/answer.blend" |
| ], |
| "evaluator": { |
| "postconfig": [ |
| { |
| "type": "upload_file", |
| "parameters": { |
| "files": [ |
| { |
| "local_path": "task-21/eval.py", |
| "path": "/home/user/Desktop/eval.py" |
| } |
| ] |
| } |
| } |
| ], |
| "func": "exact_match", |
| "result": { |
| "type": "vm_command_line", |
| "command": "python3 /home/user/Desktop/eval.py", |
| "shell": "true" |
| }, |
| "expected": { |
| "type": "rule", |
| "rules": { |
| "expected": "True\n" |
| } |
| } |
| }, |
| "proxy": false, |
| "fixed_ip": false, |
| "possibility_of_env_change": "low" |
| } |
|
|
