Finding on-screen size of boundingSphere


Short version: I’m looking for an efficient way of finding the on-screen radius of a boundingSphere.

Long version: I’m designing an on-the-fly model loader (3D Tiles is not a good match for my project). I want to load my model when its boundingSphere is in the camera frustum and big enough in screen pixels. The first part is solved, but not the secod. I have a feeling that there is a function for this somewhere in Cesium, I just haven’t found it.

Any pointers appreciated.