Download multiple children in a single request

[pjcozzi]

See When using replacement refinement, can multiple children be combined into one request?.

We may design 3D Tiles to support downloading all children in a single request by allowing tiles.json to point to a subset of a file for a tile's content similiar to glTF buffer and bufferView.

[pjcozzi]

Is anyone interested in this for the draft 1.0 spec? If so, can you please describe your use case?

[pjcozzi]

Requested by @e-andersson.

[pjcozzi]

Example:

"tiles": {
    "level1-id" : "0/0/0.b3dm"
},
// ...
"content": {
  "tile": "level1-id",
  "byteOffset": 0,
  "byteLength": 1024
}

[pjcozzi]

This will be a great feature, but am pushing 1.0 to narrow scope.

[mramato]

I know the link in the description alludes to this already, but given that HTTP/2 support is now standard in all browsers, is this still needed? Does it provide any benefit other than reducing the number of tile requests?

[GatorScott]

Not sure when HTTP/2 support became available in each browser, but keep in mind that not all users are able to use the latest browser.

[pjcozzi]

@austinEng is evaluating HTTP/2 vs. combing vs. both. Results TBA soon.

[mramato]

Awesome, looking forward to the results and methodology (since HTTP/2 server configuration probably comes into play as well)

[pjcozzi]

Would love to do this, but pushing post 1.0 for scope.

[ptrgags]

This issue came up in discussion today. Some notes:

• gRPC (or other similar library) might be useful to make a server/client architecture that can bundle tiles together in a single request
• If we do add something like this to the spec, it would be an optional architecture best used with large tilesets. Serving tilesets as static files is still a valuable feature
• this might pair well with 3DTILES_implicit_tiling in the future, as the availability buffers will be helpful in locating tiles to request on the server.

CC @lilleyse @sanjeetsuhag

[kring]

gRPC (or other similar library) might be useful to make a server/client architecture that can bundle tiles together in a single request

But HTTP/2 can already do this, right?