X3D Binary Compression Capabilities and Plans

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.

Standards

Approved ISO standard Compressed Binary Encoding (CBE) for X3D
- Based on ISO standard Fast Infoset (FI) for XML compression
Optional gzip compression and MIME Type definitions
- XML encoding (.x3dz/.x3d.gz), ClassicVRML encoding (.x3dvz/.x3dv.gz) and Compressed Binary encoding (.x3db.gz) file extensions
- Original compression technique of gzip compression for .wrl VRML called .wrz (TODO need reference). This is a common practice.

CAD Distillation Filter (CDF) technique allowing successive refinement of large X3D scenes into tighter X3D scenes
Extensible, repeatable compression and decompression algorithms for data-flow production chains
A highly effective exemplar algorithm for Coding Polygon Meshes as Compressable ASCII is demonstrated in the Experimental Binary Compression examples.
Multiple filters implemented in open-source Xj3D and X3D-Edit
Multiple other conversion and translation tools available with supporting capabilities
X3D Canonicalization (C14N) provides standardized formatting so that digital signatures are not thwarted by whitespace variations

Plan to add a further-improved X3D Compressed Binary Encoding using now-approved W3C Recommendation for Efficient XML Interchange (EXI)
Web3D contributed to EXI working group and XML Binary Characterization working group efforts
- 3D Model Compression, Serialization and Transmission use-case requirements are defined and met by EXI
Design includes compatibility with CDF techniques, XML Encryption, and XML Digital Signature for author authentication
- Relevant example scenes maintained as part of X3D Basic Examples Archive - Security
These capabilities meets most needs of digital authors for digital rights management (DRM)

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
- For example, the original August 2003 X3D Compressed Binary Encoding Request For Proposals (RFP)
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

Two independent open-source implementations available
- C++ codebase: XIOT X3D Input Output Tool library
- Java codebase: Xj3D
Ongoing status is maintained on Web3D-member wiki pages:
- Player_support_for_X3D_components
- Tool_support_for_X3D_components
Several thousand X3D Examples are available in .x3db form, encoded by Xj3D
- TODO: Plan to similarly automate conversions with XIOT for cross-check interoperability and validation testing

Web3D's X3D and CAD Working Groups each have member commitments to pursue this continued innovative work in 2012
TODO: An open workshop on 3D Transmission Formats might be a thorough way to compare candidate technologies to complete these capabilities