A key step during industrial design is the passing of design information from computer aided design (CAD) to analysis tools (CAE) and vice versa. Here, one is faced with a severe incompatibility in geometry representation: While CAD is usually based on surface representations, analysis mostly relies on volumetric representations. The forward pass, i.e., converting CAD data to computational meshes, is well understood and established. However, the same does not hold for the inverse direction, i.e., CAD reconstruction of deformed geometries resulting, e.g., from shape optimization. The few reconstruction methods reported mainly rely on spline fitting, in particular methods that rely on creating new splines simililar to shape reconstruction from 3D imaging. In contrast, this paper studies a novel approach that reuses the CAD data given in the initial design. We show that this concept leads to precise shape reconstructions while also preserving the initial notion of features defined during design. Furthermore, reusing the initial CAD representation reduces the shape reconstruction problem to a shape modification problem. We study this unique feature and show that it enables the reconstruction of CAD data from computational meshes by composing each spline in the initial CAD data with a single, global deformation spline. While post-processing is needed for use in current CAD software, this novel approach not only allows creating watertight models, but also enables reconstructing complete CAD models even from defeatured computational meshes.

翻译：工业设计中的一个关键步骤是设计信息从计算机辅助设计（CAD）工具到分析工具（CAE）的传递，反之亦然。在此过程中，面临几何表示的严重不兼容性：CAD通常基于表面表示，而分析主要依赖体积表示。正向传递，即从CAD数据到计算网格的转换，已得到充分理解和应用。然而，逆向方向——例如形状优化导致的变形几何的CAD重建——尚未有成熟的解决方案。现有少数重建方法主要依赖样条拟合，特别是类似于从3D成像进行形状重建的方法。相比之下，本文研究了一种重用初始设计中CAD数据的新方法。我们表明，这一概念不仅能实现精确的形状重建，还能保留设计阶段定义的初始特征。此外，重用初始CAD表示可将形状重建问题简化为形状修改问题。我们研究了这一独特特性，并表明通过将初始CAD数据中的每个样条与单一的全局变形样条组合，可从计算网格重建CAD数据。尽管当前CAD软件使用时需要后处理，但这种新方法不仅能创建水密模型，还能从删减特征的计算网格中重建完整的CAD模型。