Is it not possible for LOD to work when the content of a tile is another tileset.json

[Marco13]

@joking_xD

Yea, I avoided modifying GLBs as I wanted the editor to be purely for editing the 3DTiles (keeping the work flow and the purpose of the application simple so my team mates could easily understand it).
Well, at the same time I am kind of lazy and lack the time and knowledge to get the editor be able to edit the model files , I assume the research and implementing it would get quite tedious.
(I don’t really look forward to working with the vertex level data of the models )

It’s both an issue of convenience for end-users (i.e. how easy it is to accomplish a certain goal, and (ideally) understand the process while doing it), but also a technical question.

What you described unitl now focuses on the tileset JSON. You can juggle around with the JSON object, and and remove properties, and just dump a console.log(JSON.stringify...) to the console to see what’s up. Dealing with a GLB (with binary data) can be much more challenging.
(Not to mention that all this is likely happening in a browser, and a browser is… “Wahh I don’t know what a ‘file’ is!”…)

However, all this is possible, of course. You can have a look at https://gltf.report/ : You can drag-and-drop a GLB, and then there’s the <> (Scripts) tab at the left, where you can essentially write code, based on glTF-Transform, which is an unbelievably powerful library for tasks like that. The main point is: You wouldn’t have to deal with the raw data on the level of vertices and buffers.

@joking_xD

However, I do have a planned feature where I wanted to allow the users to inject metadata into the GLBs using Cesium Extensions, EXT_STRUCTURAL_METADATA and EXT_MESH_FEATURES, for mesh level picking in CesiumJS.
Which may or may not involve modifying vertex level data of the GLB files directly.

Once more the pointer to glTF-Transform: It offers the possibility to implement support for extensions. And implementations for EXT_mesh_features and EXT_structural_metadata is already part of the 3d-tiles-tools. The 3D Tiles tools are not (yet) offering a real, public API for that. And they are not (yet) deployed in a way that may be integrated into the browser. But there are some examples at 3d-tiles-tools/demos/gltf-extensions at main · CesiumGS/3d-tiles-tools · GitHub showing how certain metadata-related operations can be implemented with that.

The broader topic about metadata came up occasionally. There’s certainly a lot that can and should be done for better support here. I once opened Tools and processes for assigning and editing IDs and metadata · Issue #801 · CesiumGS/3d-tiles · GitHub (with some links to forum threads) where people asked about that. (In fact, one thread was opened pretty recently).