I have been researching how to quickly load a complex model recently, and then I discovered glTF MSFT_ Lods Extension and I’m glad Babylon supports him, MSFT_ Lods declared the material and mesh of LOD, as well as MSFT_ Screencoverage allows for both incremental loading and automatic lod in theory; But I found that currently Babylon only supports incremental loading, and there was a screenCoverages lod related logic that was deleted. Why is this 
See this thread for context on why this part has been removed:
Oh okay, so currently developers need to implement it themselves. Will there be any support plans in the future
The question has been asked several times, so I think it’s something we’ll have to consider adding back.
cc @bghgary
It would be awesome if the screen coverage worked!