Sweep1: How to adjust the blending polynomials constraints?

I am sweeping through three ellipses along a rail. The blending looks 3rd-order, but also looks like it is forcing the blend line to be perpendicular to each cross-section. This placing an unexpected ‘bulge’ prior to the middle ellipse that is awkward. I have placed a red trace in the right view which shows the outline I would prefer. How do I release the ‘perpendicularity-to-each-cross-section’ constraint from the sweep1 command?

Hi Keith, i´m not shure how to release the perpendicularity in Sweep1 but if you can draw the red trace line in the Front view and just mirror it over the X-Axis in that view, you might get the desired result using Sweep2. The red trace lines can be used then as the rails.

EDIT: You might snap to the quadrants of the ellipses to draw the trace line, then enable history and mirror before Sweep2. This gives you the option to turn points on for one trace line and tweak it…