Ideas for tile formats

[pjcozzi]

• Batched model - several models batched into one with per-model ids for interaction/metadata
  • Use case: buildings
• Instanced model - several instances of one or more models with per-instance interaction/metadata.
  • Contains: pointers to one or more internal or external (to share across tiles) glTF models, and per-instance properties, e.g., position, scale, translation, and problem-domain-specific properties.
  • Use case: trees, fire hydrants, sewer caps, lamps, traffic lights, etc.
• Composite - container with multiple heterogeneous tiles, e.g., batched model for buildings, and instanced model for trees
• Point cloud
• Vector data - including labels, POIs
• OSM - use higher-level OSM constructs to save space and then batch just-in-time client-side
• Terrain - TIN payload like quantized-mesh potentially combined with texture
• Massive models, e.g., classic Boeing 747, Power plant, etc.

[pjcozzi]

@tfili how about "Batched 3D Model" - b3dm.

Later, we would have "Instanced 3D Model" - i3dm.

[tfili]

@pjcozzi That sounds good to me. Unless I have an epiphany over the weekend I'll change it to b3dm on Monday.

[pjcozzi]

@tfili the Batched 3D Model spec is ready for your review: https://github.com/AnalyticalGraphicsInc/3d-tiles/blob/master/b3dm/README.md

Commit minor fixes to master. Open a pull request if you have major changes or comments.

[pjcozzi]

Vector data - including labels, POIs
OSM - use higher-level OSM constructs to save space and then batch just-in-time client-side

These will likely be the same format, e.g., the vector tile knows how to do extruded polygons, spheres, and other shapes that OSM uses.

[pjcozzi]

We also need to think about the name: vector vs. geometry vs. feature. Vector is probably most well-known for points, polylines, and polygons, but this tile format will go way beyond that to include, for example, what KML and Cesium already do. Geometry maps well to the Cesium API but is generic and doesn't carry the same semantics.

[pjcozzi]

These are all mentioned in the spec now with more detail.