JSON

             imoprt         export
Unity Hierarchy <=============> GLTF
    node                          nodes
        MeshFilter+MeshRenderer   meshes
        SkinnedMeshRendrerer      meshes + skins
            Materials             materials
                Textures          textures(images + samplers)

        Animation
            AnimationClip(legacy) animations

extra

BlendShapeName

• json.meshes[i].primitives[j].extras.targetNames[k]
• string

SkinMeshRoot

• json.nodes[i].extras.skinRootBone
• int(nodeIndex)

Deserialize

• UnityEngine.JsonUtlity is enough. But enum as string and dictionary type is not supported.
• SimpleJSON

WIP

• Replace json backend to UniJSON

Serrialize

It is necessary to selectively output property. UnityEngine.JsonUtlity is not enough.

• Selectively output according to JsonSchema validation
• Replace json backend to UniJSON