Object placed below 21km not visible

Hello,

Sandcastle: https://sandcastle.cesium.com/index.html#c=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

I have a problem with the visibility of the object below 21km under the terrain. I use limited terrain and I need to place an ellipsoid that will be used as an earth mantle (all over the globe not only below visible terrain). The mantle should be 30km from the terrain but if it more than 21km mantle becomes invisible when the camera above the terrain. When I disable scene3DOnly it works but that is no a solution for me. Is it possible to make ellipsoid visible with 30km depth and enabled scene3DOnly?

Thanks

Can you follow up with a screenshot or gif of what you are describing? I’m not able to reproduce the issue based on the sandcastle example.

Example:

Ellipsoid 21km from terrain - visible:

Ellipsoid 30km from terrain - not visible: