Custom User-Created Mesh Visualization

Hello,
I am trying to determine the best way to visualize a custom user-created mesh in CesiumJS. I have looked through the documentation for all the geometry primitives and entities and I don’t see anything that appears to work. I’m hoping that I’m just missing something and would love a pointer. I am looking to visualize an antenna pattern volume/mesh attached to an entity. I’ve seen examples of others doing this (e.g. image-2 here: https://cesium.com/blog/2022/11/22/mathworks-visualizing-aerospace-simulations-with-cesiumjs/) but I can’t seem to find the correct pieces to use. I appreciate any help!
Thanks,
Chris