Fit sphere into mesh which has a spherical shape

Hi , I have a segmented bone with a spherical shape at one end and would like to fit a sphere into that mesh to get the center. Does someone know how I can fit a spher (size according to the spherical shape of the bone) into my mesh? The bone is a long bone which means, that only one end is a sphere and the rest goes to the other end of the bone (see picture for better understanding). Thanks for any help!

Answer 1

[Matt J]

Isolate the end caps of the bone by finding the triangles in the mesh whose surface normals [nx,ny,nz] point strongly upward (nz>threshold). Then do a sphere fit to the points belonging to those triangles. For the latter, you can use sphericalFit(), available at

https://www.mathworks.com/matlabcentral/fileexchange/87584-object-oriented-tools-for-fitting-conics-and-quadrics