External glb file in b3dm

Hello! The b3dm spec states that an external file can be referenced instead of embedded glb. Tell me how to do it right

Can you link to the b3dm spec that you are referring to? And specifically where in the spec you are referring to?

https://github.com/CesiumGS/3d-tiles/blob/master/specification/TileFormats/Batched3DModel/README.md. Image in section “Layout”. What does “external data” mean?

To the best of my knowledge, “External Data” here does not mean the GLB itself. The GLB itself is always part of the B3DM.

But GLB can refer to “External Data”. This essentially corresponds to the image at https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#binary-gltf-layout This external data could be images or binary data. But note that this is quite unusual: In general, a binary glTF that is given as a GLB file is “self contained”, meaning that it contains all the data that is required for the asset. (It does not have to, but it usually does: Most tools that generate GLB files include all the relevant data in the file).