When you are trying to clamp to 3D tiles, Google's P3DT will be ignored. If CLAMP_TO_GROUND is selected the entity will clamp to the Cesium Globe if present but this is probably an async thing.
It is a behavior I have only been able to recreate with Google P3DT. This sandcastle also supports this, as CLAMP_TO_GROUND and CLAMP_TO_3D_TILE work as expected there. If you look at this example (make sure line 10 is commented out), you will see that the cube is "floating" relative to P3DT if either CLAMP_TO_GROUND or CLAMP_TO_3D_TILE are being used. If you toggle the globe off, the cube will snap to the 3D Tiles "ground" after a few seconds if CLAMP_TO_GROUND is being used. If CLAMP_TO_3D_TILE is being used, it will stay "floating" regardless of if the globe is toggled on or off.
Reproduction steps
Import Google P3DT
Create entity and clamp to 3D Tiles
entity will be at the "height" of the Cesium globe and not clamped to P3DT
What happened?
Entity - Clamp to 3D Tiles w/ Google P3DT
When you are trying to clamp to 3D tiles, Google's P3DT will be ignored. If
CLAMP_TO_GROUNDis selected the entity will clamp to the Cesium Globe if present but this is probably an async thing.It is a behavior I have only been able to recreate with Google P3DT. This sandcastle also supports this, as
CLAMP_TO_GROUNDandCLAMP_TO_3D_TILEwork as expected there. If you look at this example (make sure line 10 is commented out), you will see that the cube is "floating" relative to P3DT if eitherCLAMP_TO_GROUNDorCLAMP_TO_3D_TILEare being used. If you toggle the globe off, the cube will snap to the 3D Tiles "ground" after a few seconds ifCLAMP_TO_GROUNDis being used. IfCLAMP_TO_3D_TILEis being used, it will stay "floating" regardless of if the globe is toggled on or off.Reproduction steps
Sandcastle example
https://sandcastle.cesium.com/#c=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
Environment
Browser: Chrome Version 128.0.6613.138 CesiumJS Version: 1.121 Operating System: Windows