When I use a custom collection PrimitiveCollection when going to load 3 dtileset use clampToHeightMostDetailed access point elevation is always on the ground
var prititives = scene.primitives.add(new Cesium.PrimitiveCollection())
prititives.add(new Cesium.Cesium3DTileset())
Through the mode, the problem is found here
False is always returned because 3DTileset is primititives, not scene.
Thank you very much for bringing this to the community! I read through your post and looked over your code but I am still struggling to understand exactly what issue you are facing here. Could you please provide a little bit more information? A sandcastle demo showcasing the issue would also be helpful. Let me know if you have any other questions or concerns. I am looking forward to learning more about your project!
-Sam
Is this a bug? If yes, when will it be repaired?
I am not sure if this is a bug. Can you please provide an overview of the issue that you are facing here? It seems like the issue is somewhat related to point elevation - is this correct? I am looking forward to learning more 
-Sam
The 3dtileset added by new PrimitiveCollection and the 3dtileset added by scene.primitives.add(), the elevation obtained by clampToHeightMostDetailed is different
Thank you for clarifying. I suggest that you add this as an issue in the CesiumJS GitHub page.
Please let me know when you have done this and I will add details as necessary.
-Sam
