Add support for multiple contents in 3D Tiles 1.1

[engine5d]

cesium-unreal no support to load multiple contents of tileset version 1.1, like this:

"contents": [ { "uri": "batched.b3dm" }, { "uri": "batched2.b3dm" } ]

[kring]

That is true. I'm interested in hearing more about your use-case for it, because we're not quite sure at the moment how to portray multiple contents in the UI.

[engine5d]

We create a model tiling tool base on UE engine. It works well and get high performance. It share the same tileset with cesiumjs. We also use it to observe the tiling effect and performance in real time. In some case, we need to create multiple contents tile, but it is only able to show in cesiumjs.

[engine5d]

@kring Sometiles, our facility 3d model contains too many model items in a limit space like a box. In this case, we always get some tiles which file size is too large. these tiles can not load quickly for slow network speed. when loading these tiles, the cesiumjs viewer seems as if stop loading. We cut the big tile to some littile glbs for better user experience according to tileset schema version 1.1.

[kring]

when loading these tiles, the cesiumjs viewer seems as if stop loading.

Have you written an issue against CesiumJS for this problem? I'm not sure why that would happen.