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Metadata Fundamentals

Metadata is structured information that describes, explains, and locates digital assets, making them easier to discover, use, and manage across metaverse platforms.

Purpose​

Metadata serves as the foundation for asset interoperability in the metaverse. It provides a standardized way to communicate essential information about digital assets, enabling consistent representation across different platforms, ensuring proper attribution, and supporting discovery and integration.

Key Principles​

  • Standardization: Using established schemas and vocabularies ensures consistency and interoperability
  • Extensibility: The metadata model can be extended with domain-specific properties while maintaining compatibility
  • Semantic Clarity: Clear meaning of properties allows for proper interpretation across systems
  • Verification: Metadata supports content authenticity and provenance verification
  • Discoverability: Well-structured metadata enables efficient search and filtering

How It Works​

MVMD builds on JSON-LD and Schema.org to create a flexible, interoperable metadata framework for metaverse assets.

JSON-LD Structure​

JSON-LD (JavaScript Object Notation for Linked Data) provides the syntax and structure for MVMD metadata:

  • @context: Defines the vocabulary/namespaces used in the metadata
  • @type: Specifies the kind of item being described
  • Properties: Key-value pairs describing aspects of the item
  • Nested Objects: Allow for rich, structured descriptions
  • IRIs: Use web identifiers to link to external resources

Schema.org Foundation​

Schema.org provides a core vocabulary that's widely understood and adopted:

  • Types: CreativeWork, MediaObject, 3DModel, etc.
  • Properties: name, description, creator, contentUrl, etc.
  • Extensions: Additional properties beyond the core Schema.org set

Namespaces and Extensions​

Namespaces allow for domain-specific extensions:

  • Standard Namespaces: Reference established technical standards (glTF, USD, etc.)
  • Custom Namespaces: Define application-specific properties
  • Context Declaration: Map namespace prefixes to formal definitions

Example​

A basic metadata example showing fundamental structure:

{
  "@context": {
    "@vocab": "https://schema.org/",
    "mvmd": "https://mvmd.io/",
    "gltf": "https://www.khronos.org/gltf/"
  },
  "@type": "3DModel",
  "name": "Modern Chair",
  "description": "A sleek modern chair design",
  "creator": {
    "@type": "Person",
    "name": "Jane Designer",
    "url": "https://example.com/jane"
  },
  "contentUrl": "https://assets.example.com/chair.glb",
  "encodingFormat": "model/gltf-binary",
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "gltf:asset": {
    "version": "2.0",
    "generator": "ExampleStudio Exporter 2.0"
  }
}

Best Practices​

  • Include all required properties for your asset type
  • Use the most specific type possible for your asset
  • Validate your metadata against the appropriate schema
  • Keep metadata concise while including essential information
  • Use established vocabularies before creating custom properties
  • Include licensing and attribution information
  • Reference external resources with stable, persistent URLs

Common Mistakes​

  • Inconsistent Property Names: Using variant spellings or custom properties that duplicate standard ones
  • Missing Context: Omitting the @context that defines vocabularies and namespaces
  • Incorrect Types: Using inappropriate types for the asset being described
  • Shallow Metadata: Including only basic properties without domain-specific details
  • Invalid JSON-LD: Creating metadata that doesn't follow JSON-LD syntax rules

Implementation References​