I've been using POV-Ray to simulate how curved the horizon appears at different
altitudes.
I chose to use POV-Ray rather than a standard modeller (e.g. Blender) as I can
actually get a perfect (Non-polygon) sphere that way.
It also comfortably handled the 2.15GB 86400x43200 pixel texture I used for the
detail! (Blender couldn't handle it!)
https://www.youtube.com/watch?v=st-tzyisDoQ
