I have a customer that wants me to make an ellipsoid mold. The mold needs to be 3"X28"x28" with a depth of 1 1/2" at the center. I can create a dish that extends from 0" to 1 1/2" at the center. The problem is he needs that slight curve on the outer edge. The only way I could get it, or close, was create a 28" circle with a dot in the center and then use a 2 rail sweep. That created the correct outside edge but gave me a raised center. There must be an easier method.