@Stephan
<< I did the following: I draw my (center) circle on the sphere were i want it, with the given size, then intrude the circle and do on both objects a "Curve" intersect command. Now i have a circle which is exact the size of a given circle, fitting on a sphere.
how do you make the circle perpendicular to surface of the sphere before the intrude ? Because the circle can like this has any orientation
I can also draw a cylinder from the center of the sphere passing by the point I want then Curve / Intersect and killl the cylinder ! ;)
