3D Tiles facilitates efficiently streaming and rendering massive, heterogeneous 3D geospatial data such as point clouds, buildings, and photogrammetry. The 3D Tiles specification is designed to be flexible and extensible, allowing it to be used in a wide variety of domains. This talk will focus on Bentley’s/Cesium's latest efforts to add or improve support for a wide variety of data types in 3D Tiles and glTF: Gaussian splats, voxels, AEC models, and time-dynamic data. Additionally, the talk will highlight a couple of projects in the broader 3D Tiles ecosystem.

3D Gaussian Splatting, or 3DGS, was introduced at SIGGRAPH 2023 and kicked off a wave of excitement as a novel way to produce high-fidelity 3D reconstructions. Cesium has been working with folks from Bentley, Niantic Spatial, and Esri to formalize an extension for 3DGS support in glTF, as well as a corresponding extension for 3DGS compression. Adding hierarchical level-of-detail (HLOD) for efficient streaming via 3D Tiles is an active area of research.

Voxels are a common data format for many science and engineering disciplines. For example, oceanographers and climate scientists may model ocean temperatures using a voxel format. Cesium has developed an extension for 3D Tiles, and is working on a glTF extension, to add support for voxels in 3D Tiles. The voxel grid structure may be cubic, cylindrical, or spherical (the latter two are less common “in the wild”, but preferable for certain geospatial use-cases).

Many use cases for 3D Tiles are focused on the earth, but we’ve begun looking to the stars! A 3D Tiles extension for arbitrary ellipsoids has been merged, and Cesium has even published a moon terrain dataset. Preliminary discussions, though in their infancy, have begun on a potential Mars dataset.

Architecture, engineering and construction (AEC) models are becoming increasingly detailed and expansive, requiring new strategies for streaming and rendering. Cesium has created a Design Tiler for converting AEC models into 3D Tiles. IFC and OBJ files are currently supported, with ongoing efforts to add support for additional formats, such as Bentley iModel. Many enhancements (some AEC-specific, some that benefit AEC use cases but are more general) to 3D Tiles and glTF are also in the works, including improved metadata support and more flexible and efficient rendering options (see e.g. glTF extension proposals EXT_mesh_primitive_restart and EXT_mesh_primitive_edge_visibility).

Adding support for time-dynamic data has long been on the horizon for 3D Tiles. Visualizing a massive infrastructure asset, for example, is interesting and compelling, but having the ability to visualize changes over time completely changes the game. Cesium has been working on an efficient tiling scheme for time dynamic data, which is built upon 3D Tiles 1.1 and handful of new extensions (see here). The approach minimizes redundant data by only encoding changes to the tileset at discrete timestamps.

The 3D Tiles ecosystem continues to grow. The popular, cross-platform Godot game engine has added support for streaming and rendering 3D Tiles. Additionally, the web3d consortium has begun work to create a x3dom loader for 3D Tiles 1.1.