The loft tool can be used to make something like an ellipsoid. This video begins by using a box as defining geometry for three elliptical sketches. The ellipse in each sketch is split into quarters using the "break" sketch tool.
Once we have suitable quarter-ellipses, use the loft tool to create one eighth of the final surface. Before opening the loft tool, build three surface-extrudes to be used as support surfaces for the loft. The surface-extrudes are based on a quarter-ellipse.
The loft is built using two profiles. Profile 1 is a quarter-ellipse edge on one of the support surfaces. Set tangency to be G1. Profile 2 is a point at the opposing corner. We also supply two rails for the loft. Each rail is an edge on onf of the remaining support surfaces, and each rail has a G1 continuity set.
The loft can be mirrored three times to make the whole result. Zebra lines (under Analysis) can be used to inspect the continuity of the result and alert us if, for example, we forgot one of the continuity constraints on the loft.
This final surface is an approximation to an ellipsoid.
