The EXtensible 3D Graphics standard X3D (http://www.web3d.org/realtime-3d/x3d/what-x3d) continues to evolve include more capabilities and improve the clarity and consistency of its specifications. The third upgrade to X3D (V3.3) release expands X3D capability to include volume visualization, user-selectable units and internal technical changes, and it is in final draft ballot at ISO with an expected release by summer 2013. The publicly released V3.3 specification documents are available at http://www.web3d.org/realtime-3d/specification/version/V3.3. This work advances X3D as the leading royalty-free open standard and run-time architecture to represent and communicate 3D scenes and objects using XML.

The X3D V3.3 standard includes significant new functionality for cross-platform, reproducible interactive 3D presentations of anatomic volumetric data (e.g. CT, MRI, PET scan, and ultrasound), annotations, CAD models as well as the integration of semantic knowledge-bases (i.e. medical ontologies such as SNOMED CT). As a Web standard, these rendered displays can be distributed and shared through secure services and applied to other domains such as non-invasive sensing and geophysics. The Web3D Consortium Medical Working Group authored the specification and has successfully demonstrated several applications with international collaborators including informed consent, anatomic education, and surgical training.

"The new support for expressive volume rendering styles and annotations in X3D V3.3 is a milestone for international interoperability within and across the healthcare enterprise. As a web-aware platform for reproducible medical presentations, such an open-standard is an integral tool in the effort to lower costs and improve quality of care." emphasized Michael Aratow, MD, FACEP and Co-Chair of the Medical Working Group. The functionality for the interchange of volumetric, polygonal and textual visualizations is collected into a X3D node set specified as the Medical Interchange Profile, allowing for software development utilizing only a small, focused subset of the entire X3D specification relevant to clinical care.

Another significant change is the addition of user-definable units through the creation of the new UNIT statement.  The user can select the units of choice from Angstroms to light-years, with similar choices for angle, force, and mass. X3D will handle all of the conversions from other units (e.g., speed) and other models dependent on these base units. This powerful new feature allows model builders to construct their model in the unit most appropriate for their work.

In addition, significant work has taken place to improve the overall design consistency of the entire X3D standard. This includes making the Geospatial Component more compatible with the Navigation Component, as well as ensuring that field inheritance is now fully consistent. Most notably, this all been achieved with minimal or no effect on backwards compatibility.