Geometric surface patches without twist constraints (Q1819531)

The author presents an interpolation scheme which assumes not only function values and derivatives but also curvature values on the boundary of an arbitrary triangle. Following \textit{G. Nielson}'s method [J. Approximation Theory 25, 318-336 (1979; Zbl 0401.41005)] he uses a geometric Hermite-operator along line segments joining a vertex and a side. Barycentric coordinates are used.