Automatic reconstruction of 3D topology optimization to editable CAD model with rotation minimizing frames

Abstract Topology optimization can automatically generate the optimized topology under various boundary conditions. However, optimized results usually lack compatibility with computer-aided design (CAD) systems, necessitating time-consuming and laborious manual reconfiguration, thereby significantly reducing the efficiency of the designing process. This paper presents a novel automatic construction to generate an editable and closed CAD model based on the parametric surface for those tending toward beam-like structures. The process can be divided into three parts: pre-processing, solution, and post-processing. In the pre-processing stage, a complete and easy to implement multi-level hybrid topological data structure is proposed for automated reconstruction. In the solution stage, the rotation minimizing frames are calculated to generate the lofting surfaces with minimal twists. Meanwhile, the proposed principal plane projection addresses the robust reconstruction of the multiple freeform cross-sections. The reconstructed model is performed with Boolean union operations with non-designed domains in the post-processing stage. Five case studies are provided to validate the effectiveness of this new approach to obtain the editable CAD model. The derived CAD model is pivotal in subsequent applications, such as assembly constraints, simulation analysis, and parametric design.