Enforce standard node naming and animation baking in wearables

[cazala]

Problem We've identified two issues affecting emote playback in wearables:

1. Non-standard node naming:

   • Some wearables use non-standard names for skeleton nodes (e.g., "Armature.001" instead of "Armature")
   • This breaks compatibility with emotes that expect standard node names
   • While we've patched the preview to handle numeric suffixes, other naming variations could still cause issues

2. Animation dependency on skeleton hierarchy:

   • Some emotes (like the DAO Pony emote) use a mixed animation approach:
     • Main motion is applied to the Armature node
     • Short positioning animations are applied to individual bones
   • This approach relies on proper skeleton hierarchy for bone inheritance
   • If the Armature node isn't found or properly named, the entire animation fails

Solution The Wearable Editor should automatically validate these issues before allowing wearable publication:

1. Node Name Validation:

   • Scan the GLB file's node hierarchy
   • Check for standard DCL node naming convention
   • Flag any deviations from the standard naming (e.g., "Armature.001", "Avatar_Head.001")
   • Prevent users from publishing such GLB and show them the faulty names of the nodes.

2. Animation Baking Validation:

   • Analyze animation data in the GLB
   • Detect if animations are properly baked to all relevant bones
   • Flag animations that only target the Armature without full bone baking
   • Warn users that this approach of animation could not work on legacy emotes that don't have a propery skeleton hierarchy, encourage them to bake animations in all bones.

Implementation Path

1. GLB Inspection:

   • Use existing GLB parsing libraries (like @babylonjs/core) to load and inspect models
   • Create a validation module that:
     • Lists all nodes in the hierarchy
     • Identifies standard DCL node names vs non-standard ones
     • Maps animation targets and their keyframes

2. Validation Rules:

   • Define a list of standard DCL node names
   • Create rules for valid node naming patterns
   • Define requirements for animation baking coverage

3. UI Integration:

   • Add validation step in the import provess
   • Show clear error messages for naming issues
   • Show warning messages for animation issues

4. Documentation:

   • Update wearable creation guidelines
   • Document standard node naming requirements
   • Explain animation baking best practices

This enhancement will improve wearable compatibility and reduce animation issues in the platform. It can be tested using the BabylonJS Sandbox (https://sandbox.babylonjs.com) to verify proper node naming and animation baking.

Related

• Preview fix PR: https://github.com/decentraland/wearable-preview/pull/119

[cazala]

These are the name conventions for the skeleton of the wearables:

Root

• Armature

Base Structure

• Avatar_Hips
• Avatar_Spine
• Avatar_Spine1
• Avatar_Spine2

Head

• Avatar_Neck
• Avatar_Head

Left Arm

• Avatar_LeftShoulder
• Avatar_LeftArm
• Avatar_LeftForeArm
• Avatar_LeftHand

Left Hand Fingers

• Avatar_LeftHandThumb1
• Avatar_LeftHandThumb2
• Avatar_LeftHandThumb3
• Avatar_LeftHandThumb4
• Avatar_LeftHandIndex1
• Avatar_LeftHandIndex2
• Avatar_LeftHandIndex3
• Avatar_LeftHandIndex4
• Avatar_LeftHandMiddle1
• Avatar_LeftHandMiddle2
• Avatar_LeftHandMiddle3
• Avatar_LeftHandMiddle4
• Avatar_LeftHandRing1
• Avatar_LeftHandRing2
• Avatar_LeftHandRing3
• Avatar_LeftHandRing4
• Avatar_LeftHandPinky1
• Avatar_LeftHandPinky2
• Avatar_LeftHandPinky3
• Avatar_LeftHandPinky4

Right Arm

• Avatar_RightShoulder
• Avatar_RightArm
• Avatar_RightForeArm
• Avatar_RightHand

Right Hand Fingers

• Avatar_RightHandThumb1
• Avatar_RightHandThumb2
• Avatar_RightHandThumb3
• Avatar_RightHandThumb4
• Avatar_RightHandIndex1
• Avatar_RightHandIndex2
• Avatar_RightHandIndex3
• Avatar_RightHandIndex4
• Avatar_RightHandMiddle1
• Avatar_RightHandMiddle2
• Avatar_RightHandMiddle3
• Avatar_RightHandMiddle4
• Avatar_RightHandRing1
• Avatar_RightHandRing2
• Avatar_RightHandRing3
• Avatar_RightHandRing4
• Avatar_RightHandPinky1
• Avatar_RightHandPinky2
• Avatar_RightHandPinky3
• Avatar_RightHandPinky4

Legs

• Avatar_LeftUpLeg
• Avatar_LeftLeg
• Avatar_LeftFoot
• Avatar_LeftToeBase
• Avatar_RightUpLeg
• Avatar_RightLeg
• Avatar_RightFoot
• Avatar_RightToeBase