Thanks a lot for your answers! I see, getting an exact solution to this problem seems very complex. I will look into Kenneth's idea then and try to get an approximate value based on eigenvectors. Thanks again :) Le mar. 23 juin 2020 à 22:24, Kenneth Sloan <kennethrsloan@gmail.com> a écrit : > There are several ways to get approximate answers to your question. > > The method I prefer is to use principal component analysis (Eigenvectors). > First, you need a well-distributed set of points from the object. Since we > are approximating, perhaps the set of vertices on the boundary is > sufficient. Check wikipedia for the details on PCA, Hessian, and > Eigenvectors. This will get you a set of 3 axes. You can then scale these > to make the volume of the ellipsoid match the volume of the object. > > Finding an exact solution looks extremely difficult. I’m not even sure > the solution is unique. > > -- > Kenneth Sloan > KennethRSloan@gmail.com > Vision is the art of seeing what is invisible to others. > > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >