Robust surface reconstruction for topology optimization using Catmull-Clark subdivisions

Topology optimization (TO) yields structurally optimal designs, but the output is typically represented by faceted, poor-quality surface meshes that are inadequate for high-fidelity simulation and downstream design and manufacturing. This paper proposes an automated framework for transforming raw TO results into smooth, watertight, and CAD-compatible B-rep models that can be directly integrated for subsequent product design. The method capitalizes on the underlying structural topology by first extracting a curve skeleton, which acts as a high-level descriptor of the design’s form and connectivity. This skeleton guides a structured, block-based reconstruction, where junction orientations are determined and branch cross-sections are profiled via ray-casting. A manifold, pure quadrilateral mesh is then generated through a skeletal-driven extrusion process. To ensure high quality resulting surfaces, the initial quad-dominant layout is regularized and subsequently represented by an initial smooth subdivision surface. The geometry is further aligned with the target TO output through a subdivision-based surface reconstruction algorithm, enhanced by a curvature-driven fairness energy. The final output is a geometrically faithful representation of the input raw TO mesh model with a high-level smooth surface, designed for direct integration into downstream workflows. The effectiveness of the method is validated on benchmark compliance minimization problems, demonstrating its capacity to transform intricate, optimized topological structures into manufacturable, high-quality surface models. • Present a robust and automated framework for TO-to-CAD construction. • It converts raw TO results into watertight, high-quality subdivision surface models. • Develop an algorithm for efficient sparse anisotropic quad mesh generation. • The quad mesh is well suited for Catmull-Clark subdivision surface recon- struction. • Produce a CAD-compatible B-rep model for downstream design and man- ufacturing.