Liaison between Khronos and Open Geospatial Consortium Leads to 3D Tiles Community Standard Built on glTF for Streaming Massive Models

To jointly advance accessibility of 3D geospatial content, The Khronos®Group recently formalized a liaison with the Open Geospatial Consortium (OGC). One of the first victories of this collaboration between the computer graphics and geospatial communities is a new OGC Community Standard addressing massive scale 3D pioneered by longtime Khronos contributors, the Cesium team.

The OGC just adopted 3D Tiles as a Community Standard for streaming and rendering massive 3D content, like photogrammetry, 3D buildings, BIM/CAD, instanced features, and point clouds. The open format builds on glTF™, citing it as a normative reference for its runtime efficiency, interoperability, and strong software ecosystem.

Photogrammetry model covering about 150 square kilometers of Melbourne, Australia, tiled using Cesium ion from 10-centimeter resolution data provided by Aero3DPro.

3D Tiles supports heterogeneous 3D content. Here in a scene of Penn State University, a proposed chemistry building CAD model is fused with existing photogrammetry data in a CesiumJS app, courtesy of Bentley Systems.

Data providers, from industries such as drone data capture, indoor mapping, mixed reality, and emergency response efforts, are rapidly accumulating geospatial 3D content across a variety of formats. These formats are too numerous for renderers to realistically support but can be converted to 3D Tiles for optimized streaming and rendering.

3D Tiles defines a spatial hierarchy and efficient batching for rendering with hierarchical level of detail (HLOD). Metadata for features--individual components of a mesh, such as a building or tree--is commonly used with 3D Tiles Styling, an expression language describing the appearance of a feature at runtime.

“The recent liaison agreement between Khronos and OGC has now come to life with the 3D Tiles Community Standard being built on Khronos’ glTF 3D transmission format,”says Neil Trevett, President of the Khronos Group. “It’s great to see the first fruits of this liaison, and Khronos is looking forward to more opportunities to build valuable standards and initiatives for the geospatial industry in cooperation with OGC.”

OGC Executive Director of the Standards Program, Scott Simmons, commented: “The hard work of the Cesium team at AGI in developing the 3D Tiles specification is the realization of the value in partnership between standards development organizations. Khronos and OGC each have great core expertise, and we have been able to leverage what we each do best in a cooperative fashion to provide a standard that is modern in approach and able to satisfy very demanding user requirements.”

As longtime contributors to glTF, the Cesium team is excited to see how 3D Tiles will grow the ecosystem by applying it to the world of 3D geospatial. For all things 3D Tiles, including pipelines for generating 3D Tiles, visit the Cesium platform at cesium.com.