ISTHMUS: Interfacing Surface Triangles and voxels for Heterogeneous MUltiphysics Simulations

ISTHMUS is a software package designed to couple voxel-based domains with surface mesh-based solvers. Voxelized geometries provide high-fidelity representations of materials but are difficult to integrate into multiphysics workflows because of jagged boundaries and the absence of robust interface mapping. ISTHMUS addresses this challenge through two key modules: motion mapping and flux mapping. The software is written in Python with performance-critical routines accelerated on GPUs via CUDA. ISTHMUS is solver-agnostic, enabling coupling of a wide range of fluid, thermal, and structural codes without requiring modifications to their discretizations.