Generating body-fitted particle distribution for arbitrarily complex geometry underpins the applications of particle-based method to engineering and bioengineering and is highly challenging, and thus hinders the potential of particle methods. In this paper, we present a new computer-aided design (CAD) compatible body-fitted particle generator, termed as CAD-BPG, for arbitrarily complex 3-D geometry. By parsing a CAD model, the present method can accurately tackle arbitrarily complex geometry representation and describe the corresponding geometry surface by constructing an implicit zero level-set function on Cartesian background mesh. To achieve a body-fitted and isotropic particle distribution, physics-driven relaxation process with surface bounding governed by the transport-velocity formulation of smoothed particle hydrodynamics (SPH) methodology is conducted to characterize the particle evolution. A set of examples, ranging from propeller, stent structures and anatomical heart models, show simplicity, accuracy and versatility of the present CAD-BPG for generating body-fitted particle distribution of arbitrarily complex 3-D geometry. Last but not least, the present CAD-BPG is applied for modeling wave-structure interaction, where wave interaction with an oscillating wave surge converter is studied, and the results show that the present method not only provides an efficient and easy-to-implement pre-processing tool for particle-based simulation but also improves the numerical accuracy compared with lattice particle distribution. Consequently, the propose CAD-BPG sheds light on simulating real-world applications by particle-based methods for researchers and engineers.

为任意复杂的几何体生成适合人体的粒子分布，为基于粒子的方法在工程和生物工程中的应用奠定了基础，并且具有很高的挑战性，因此阻碍了粒子方法的潜力。在本文中，我们提出了一种新的计算机辅助设计（CAD）兼容的人体装配粒子生成器，称为CAD-BPG，用于任意复杂的3D几何形状。通过解析CAD模型，通过在笛卡尔背景网格上构造隐式零水平集函数，本方法可以准确地解决任意复杂的几何表示并描述相应的几何表面。为了实现贴身和各向同性的粒子分布，进行了物理驱动的弛豫过程，其表面边界受光滑粒子流体动力学（SPH）方法的传输速度公式控制，以表征粒子的演化。一组示例，范围涵盖螺旋桨，支架结构和解剖心脏模型，显示了本CAD-BPG的简单性，准确性和多功能性，可用于生成人体拟合的任意3D几何形状的粒子分布。最后但并非最不重要的一点是，本CAD-BPG用于建模波结构相互作用，其中研究了与振荡波浪涌转换器的波相互作用，结果表明，本方法不仅提供了一种有效且易于实现的方法用于基于粒子的模拟的预处理工具，但与点阵粒子分布相比，它还可以提高数值精度。