Topic: 3D model formats for urban planning & their use with/in Augmented Reality

When selecting and preparing for the 3D Geospatial Geneva project, we requested data sets from the city of Geneva and provided these upon request to developers of mobile applications to produce geospatially-anchored learning and visualizations. The project appealed to developers of urban AR experiences but not limited to AR.

In this process, we came upon a very significant obstacle to our developers. The obstacle involves the 3D city/building model formats. The authoring systems architects choose 3D formats they use internally, based on the use cases and requirements, but there is a great diversity of file formats available and they do not always include the formats used in city planning/city data managers.

Diversity of semantics present a significant set of obstacles associated with use of (3D) models. Semantics abstracts the physical world with data for a purpose.

3D geometry captures the physical properties of the real world. 3D models can include the geometry and the associated data.

The diversity of 3D representations from which to choose comes about as a result of

• Complexity of the real world
• Complexity of 3D geometry and how to express the notion of volume (totally different principles of how to express geometry) some are optimized for visualization, some optimized for easy editing, Those who work with 3D are aware of three very basic models to express geometry:
  • Wireframe (low options)
  • Surface model (tessellated or original geometry)
  • Volumetric model (many options)
• Proprietary formats (many of these, optimized for different use cases)
• Originally developed to be open formats (also many of these)

The diversity of 3D formats prevents interoperability and disrupts the workflow of people making 3D-enhanced and/or 3D model-based workflows, experiences and content.