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      How to export Bone-Based Animations from 3ds Max to GLB (for USDZ)

      Exporting mesh animations using Bones and Skin Modifier, compatible with USDZ. Ideal for rigged objects like mechanical parts, furniture with moving pieces, or characters.

      Step 1: Prepare your mesh

      1. Attach all parts (e.g., cabinet + drawers) into a single mesh
        1. Right-click → Convert to Editable Poly
        2. Use Attach to merge all objects
      2. Rename the mesh clearly (e.g., Cabinet_Main)

      Animation 2

      Step 2: Create a skeleton (bone hierarchy)

      1. Go to Create > Systems > Bones
      2. Create one bone per animated part (e.g., Bone_Drawer1, Bone_Drawer2, etc.)
      3. Create a Dummy or extra bone as the root (e.g., Root_Bone)
      4. Use Select and Link to parent all bones to the root:

      Animation 3

      Step 3: Skin the mesh

      1. Select the mesh and apply a Skin Modifier
      2. In Add Bones, add all bones (Bone_Drawer1, etc.)
      3. Assign vertices to each bone:
        1. Enter Envelope mode
        2. Enable Vertices + Select
        3. Select the correct vertices per part
        4. Use Assign Weight or Weight Tool to set 1.0 weight to the matching bone

      Only assign each group of vertices to one bone for rigid motion (no deformation).

      Animation 4

      Step 4: Animate the bones

      1. Enable Auto Key
      2. Animate each bone at different frames (e.g., drawers moving forward)
      3. Make sure the bones are moving, not the mesh directly

      Step 5: Export with Babylon

      1. Menu: Rendering > Babylon File Exporter
      2. Set format to .glb

      Check these options:

      • Export animations
      • Auto bake animations
      • Export tangents (optional for normal maps)
      • Export only selected (if needed)
      • Important: Babylon supports only one SkinnedMesh per skeleton hierarchy

      Notes

      • All bones must be under a single root hierarchy (Dummy or Bone)
      • Only one mesh with one Skin Modifier allowed
      • Perfect for structured motions (drawers, robotic arms, etc.)
      • USDZ does not support multiple skins or morph targets

      Animation 3

      Important Note: Avoid 2-Sided Materials

      USDZ does not support 2-sided materials. Using them may result in faces not rendering correctly or disappearing in AR viewers (such as iOS Quick Look or Safari).

      To ensure proper compatibility:

      • Do not enable the 2-Sided checkbox in Standard or Physical Materials
      • Avoid using the 2-Sided Material shader node (with Front and Back slots)
      • Always check your face normals and ensure they are facing outward
      • If you need both sides visible, duplicate the geometry and flip normals manually

      Use the Normal modifier in 3ds Max or manually flip polygons in sub-object mode to correct normals.