Interoperability Requirements for 3D Printing, Scanning, Visualization

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Digital thread nexus between model-based 3D Virtual Environments and 3D print models.
Submitted by alex.viana on Sat, 03/02/2019 - 10:00
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by Alex Viana NAVFAC and Don Brutzman NPS

3D models can be interoperable for Additive Manufacturing  (AM) and Virtual Environments (VEs).   Example operational requirements include capability for Naval and Joint forces to conduct real-time 3D communications over multiple networks, ability to conduct model-based logistics rehearsal in geo-enabled 3D virtual environments, and enabling digital-thread compatibility to deliver 3D models to networked 3D printers.

Scanned 3D models can be adapted for publication in X3D form.  Common preparation steps include distillation of point clouds into discrete meshes, correlation of geometry, and addition of metadata.  The Web3D Consortium's Design, Printing and Scanning Working Group is encouraging converter support and documenting best practices.

X3D supplements use of STL.  Best practices for publishing 3D-printable models and 3D scanning data using the X3D Graphics International Standard also support visualization over the Web. Some 3D printing software (such as the popular Cura application) support X3D usage directly already.  Observing simple compatibility requirements and adding model metadata enables integration into collaborative virtual environments such as SPIDERS3D.  This page describes archival publishing requirements for  X3D models to achieve successful digital interoperability.

Interoperability Considerations 

3D models are diverse and can be created in a wide variety of formats. Some are open, some are proprietary, most require special software tools for viewing and handling. Often the maximum fidelity needed for engineering and construction purposes requires customized software tools for full functionality.   Such uniqueness and "lock in" is necessary for licensed reproduction of commercial parts, but also can inhibit re-use across the full mission life cycle of government users.  Legitimate government and industry needs for additional viewing, printing, and adaptation can be met through publication of sharable versions.

Extensible 3D (X3D) Graphics is designed for Web publication of diverse 3D models. Feature support includes 3D visualization, 3D printing, and 3D scanning. Additional features include structured metadata, animation, interaction and user navigation which can document and showcase model capabilities.  X3D Resources include dozens of dozens of conversion paths for converting, creating, validating and publishing X3D that might originate from a variety of formats.

X3D is royalty free for any use, has over two decades of demonstrated interoperability, and continues to steadily evolve through standards development by Web3D Consortium working groups. HTML compatibility simplifies X3D publication for easy sharing and viewing.  Years of rigorous implementation and evaluation work now enables long-term archival stability, and durability for reuse, as a publishing option for almost any 3D model of interest.

Shared Use of Printable Models in Virtual Environments

Common conventions are essential for consistent 3D model reuse. In order to support composition for visualization in 3D virtual environments such as SPIDERS3D, the following requirements pertain.

Model and Format Requirements

  • General 3D deliverables in engineering formats also include X3D, VRML or STL versions for inspection and reuse.
  • Model fidelity must be sufficient for shared viewing and 3D printing for visualization.
  • Model correctness is confirmed using X3D Validator or other X3D Quality Assurance (QA) tools.
  • Model files maintained in X3D Canonical Form can be digitally signed, encrypted and compressed.

Spatial Requirements

  • Model units must be in meters, or else have units declared, matching the X3D specification.
  • Coordinate-system origin (0 0 0) is at the model center or the ground level.
  • Default X-Y-Z directions are important: Y-axis is up, X-axis is through front, Z-axis is through right side.

Metadata Requirements

  • Metadata information about model access, licensing, permissions and provenance is required. 
  • Metadata information is attached or included within X3D model files.
  • Additional amplifying metadata is embedded within subset files as appropriate.
  • Example templates show how common well-defined metadata vocabularies are applied.

Additional Resources

Next Steps

Best practices for 3D publication are emerging.  We look forward to establishing basic patterns for scalable progress by publishing X3D models from diverse submissions that are compatible within SPIDERS3D and other large-scale virtual environments.