Interactive synthesis of physical sound effects is crucial in digital media production. Sound radiation simulation, a key component of physically based sound synthesis, has posed challenges in the context of complex object boundaries. Previous methods, such as ghost cell-based finite-difference time-domain (FDTD) wave solver, have struggled to address these challenges, leading to large errors and failures in complex boundaries because of the limitation of ghost cells. We present SonicRadiation, a hybrid numerical solution capable of handling complex and dynamic object boundaries in sound radiation simulation without relying on ghost cells. We derive a consistent formulation to connect the physical quantities on grid cells in FDTD with the boundary elements in the time-domain boundary element method (TDBEM). Hereby, we propose a boundary grid synchronization strategy to seamlessly integrate TDBEM with FDTD while maintaining high numerical accuracy. Our method holds both advantages from the accuracy of TDBEM for the near-field and the efficiency of FDTD for the far-field. Experimental results demonstrate the superiority of our method in sound radiation simulation over previous approaches in terms of accuracy and efficiency, particularly in complex scenes, further validating its effectiveness.

翻译：物理声效的交互合成在数字媒体制作中至关重要。作为物理声学合成的关键组成部分，声辐射模拟在复杂物体边界场景中面临持续挑战。此前基于虚拟网格的时域有限差分法（FDTD）波场求解器因虚拟网格的局限性，难以有效应对复杂边界的挑战，导致较大误差与求解失效。本文提出SonicRadiation——一种无需依赖虚拟网格、可处理复杂动态物体边界的混合数值声辐射求解方案。我们推导出将FDTD网格单元物理量与边界元法（TDBEM）时域边界元量统一表达的相容公式，继而提出边界网格同步策略，在保持高数值精度的同时实现TDBEM与FDTD的无缝耦合。该方法兼具TDBEM近场精度优势与FDTD远场计算效率。实验结果表明，在声辐射模拟中，本方法在精度与效率上均显著优于既有方案，尤其适用于复杂场景，进一步验证了其有效性。