Is it possible to calculate the center of an incomplete sphere? An in-Blender solution would be preferred so I don't have to switch programs, but other tools are welcome too.
I'm testing out face rigging via Blender's built-in Rigify plugin, and it suggests defining a pivot based on a spherical shape. However, I only have a small-curvature concentric-ring mesh per eye on my test model (it's imported from a program that generally doesn't use complete spheres for eyes). Is there a way I can calculate the center of the would-be sphere using just the irises? Thanks!
The shipped add-on tinyCAD has a 'Resurrect Circle Center' operation, which finds the circumcenter of a triangle of 3 vertices.
If you select 3 vertices from your sphere-section, which lie on one of the sphere's great circles, it will place the 3D cursor at the center of the complete sphere, and draw the great circle in the plane of the vertices.