Instead of a quadrangular surface, you can use a B‑spline surface. The shape of this can be adjusted retrospectively, using the integrated help nodes. Depending on the necessary surface complexity, you can create a B‑spline surface with 3 × 3 or 4 × 4 help nodes.
In addition to arcs and circles, SHAPE-THIN 8.xx allows you to model the following curved cross-section parts: ellipses, elliptical arcs, parabolas, hyperbolas, splines, NURBS (non-uniform rational B-Spline).