Curved geometry modeling: interpolation of subdivision features

Abstract

We present a nodal interpolation method to approximate a subdivision model. The main application is to model and represent curved geometry without gaps and preserving the required simulation intent. Accordingly, the technique is devised to maintain the necessary sharp features and smooth the indicated ones. This sharp-to-smooth modeling capability handles unstructured configurations of the simulation points, curves, and surfaces. These surfaces are described by the initial triangulation composed of linear triangles with the same surface identifier, and determine the sharp point and curve features. Automatically, the method suggests a subset of sharp features to smooth which the user modifies to obtain a limit model preserving the initial points. This model reconstructs the curvature by subdividing the initial triangular mesh, with no need of an underlying curved geometry model. Finally, given a polynomial degree and a nodal distribution, the method generates a piece-wise polynomial representation interpolating the limit model. Numerical evidence suggests that this approximation, naturally aligned to the subdivision features, converges to the model geometrically with the polynomial degree for fair nodal distributions.We also apply the method to prescribe the curved boundary of a high-order volume mesh. We conclude that our sharp-to-smooth modeling capability leads to curved geometry representations with enhanced preservation of the simulation intent.