X3D Binary Compression Capabilities and Plans

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Synopsis: Lots of work has been accomplished towards proper support of X3D Binary Compression for a wide variety of potential uses.

X3D appears to have have an 80% solution already available that meets various requirements for a general 3D transmission format.

  • TODO: We are updating this page and creating a draft 2013 Call For Contributions to further progress these technical capabilities for X3D.

Existing Compression Usage for X3D and VRML97

  • Approved ISO standard Compressed Binary Encoding (CBE) for X3D.
  • Optional, alternative gzip compression and MIME Type definitions for X3D.
  • Optional, alternative gzip compression for VRML97.
    • Original compression technique of applying gzip to .wrl compressed VRML97 files was called .wrz.
    • This emerged as a common practice when gzip was originally used. No formal specification of .wrz or corresponding mime type was produced.
    • Occasionally authors might also gzip .wrl files while retaining the .wrl file extension.

Polygon Reduction and Geometric Compression

Formal specifications:

Best practices:

Data-Centric Binary Encodings

Network Streaming

  • Multiple capabilities are already available in X3D for flexible network transmission.
    • Anchor, Inline, LOD, LoadSensor, Script and Prototype nodes support successive retrieval of content once initial model is displayed.
  • TODO: Willing to consider further addition of progressive-mesh geometric streaming technologies, perhaps by a public Call for Contributions. Note however that an effective progressive-mesh approach is likely dependent on the availability of a corresponding mesh compression algorithm.
  • Intellectual Property Rights (IPR) protections for X3D specification.
    • Patented technologies can be considered, but only when eventual use will be royalty free for X3D use (if eventually accepted).
    • Submitters can restrict access to patented submissions during member-only working group review, if desired.
  • TODO: Use cases and test examples can demonstrate whether http/https and local-file url retrieval are sufficient for a network protocol.
    • Other network protocols (Web sockets, P2P channels, etc.) might be possible, but only if security restrictions can be handled satisfactorily.

X3D Implementations

The following tools implement the X3D Compressed Binary Encoding (CBE) standard.

Looking Ahead

  • Web3D's X3D and CAD Working Groups each have member commitments to pursue this continued innovative work in 2013.
  • TODO: An open workshop on 3D Transmission Formats might be a thorough way to compare candidate technologies to complete these capabilities.
  • Consider common, sharable technical strategies with MPEG-4 and Collada.