re sphere from points in article qkgbuinns n shelley u washington edu bolson carson u washington edu edward bolson writes boy this will be embarassing if it is trivial or an faq center and radius exactly fitting those points i know how to do it for a circle from points but do not immediately see a straightforward way to do it in d i have checked some geometry books graphics gems and farin but am still at a loss please have mercy on me and provide the solution off the top of my head i might try given p p p p find p c center of sphere determined by p p dist p c p i radius p c is the same distance from our four points so dist p c p dist p c p dist p c p dist p c p of course we can square the whole thing to get rid of square roots distsq p c p distsq p c p distsq p c p distsq p c p plug in the variables into the distance formula simplify and the x c y c and z c terms cancel out leaving you with three linearly independent equations and three unknowns x c y c z c solve using your favorite method all the best john dr john s eickemeyer the lord god is subtle information technology institute but malicious he is not national computer board singapore email johne iti gov sg albert einstein
