This was asked on the old Google Groups forum here:
How does cesium ion server perform tiling for 3D tiles? when i zoom in, cesium render new tileset.json and .b3dm files .I think it’s automaticly renderedfrom cesium ion server but admitting that i have a huge dataset of .b3dm files and i want to host these data to a custom server to render them in a cesium app ,How does the client know with b3dm to render depending on zoom level?
Cesium ion has several different pipelines depending on what type of data you have in order to produce efficient tiles. If you’re trying to create an efficient 3D Tileset, try uploading your source models (like the OBJ/glTF models etc) to Cesium ion.
A 3D Tileset contains information on bounding volumes and geometric error, which is what the client uses to compute what tiles need to be rendered. You can read more about this in section 7 of the 3D Tiles overview here: