Hello!
I am trying to developing Viewshed Analysis with Cesium for Unity 
Viewshed Analysis Example.
I found a unity forum thread about this ( not releated with Cesium for Unity)
https://forum.unity.com/threads/display-a-viewshed-in-a-3d-worldspace.530866/
is there anyone who trying to develop this feature?
or is there any asset or open sources that useful to implement this?
and also I found a paper for this. if anyone who interested in this topic, then check this.
https://www.tandfonline.com/doi/full/10.1080/17538947.2011.555565
If you know please share with me
Thanks!