ISTHMUS: Interfacing Surface Triangles and voxels for Heterogeneous MUltiphysics Simulations

Ahmed H. Yassin; Ethan H. Huff; Vijay B. Mohan Ramu; Bruno Tacchi; Carlos E. Américo; Tyler D. Stoffel; Savio J. Poovathingal

doi:10.1016/j.softx.2026.102660

ISTHMUS: Interfacing Surface Triangles and voxels for Heterogeneous MUltiphysics Simulations

Ahmed H. Yassin
, Ethan H. Huff
, Vijay B. Mohan Ramu
, Bruno Tacchi
, Carlos E. Américo
, Tyler D. Stoffel
, Savio J. Poovathingal

Research output: Contribution to journal › Article › peer-review

Abstract

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.

Original language	English
Article number	102660
Journal	SoftwareX
Volume	34
DOIs	https://doi.org/10.1016/j.softx.2026.102660
State	Published - Jun 2026

Bibliographical note

Publisher Copyright:
© 2026 The Author(s).

Funding

The research was sponsored by DEVCOM-ARL and was accomplished under Cooperative Agreement Numbers W911NF-21-2-0075 and W911NF-19-2-0152. This work was also based upon work supported by the Office of the Under Secretary of Defense for Research and Engineering under award number FA9550-22-1-0342. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the ARL or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein.

Funders	Funder number
DEVCOM Army Research Laboratory	W911NF-19-2-0152, W911NF-21-2-0075
Office of the Under Secretary of Defense for Research and Engineering	FA9550-22-1-0342

Keywords

Differential ablation
Fluid-structure interactions
Fluid-thermal interactions
Marching windows
Mesoscale coupling
Voxel-to-surface map

ASJC Scopus subject areas

Software
Computer Science Applications

Access to Document

10.1016/j.softx.2026.102660

Cite this

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title = "ISTHMUS: Interfacing Surface Triangles and voxels for Heterogeneous MUltiphysics Simulations",

abstract = "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.",

keywords = "Differential ablation, Fluid-structure interactions, Fluid-thermal interactions, Marching windows, Mesoscale coupling, Voxel-to-surface map",

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month = jun,

doi = "10.1016/j.softx.2026.102660",

language = "English",

volume = "34",

journal = "SoftwareX",

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AU - Yassin, Ahmed H.

AU - Huff, Ethan H.

AU - Mohan Ramu, Vijay B.

AU - Tacchi, Bruno

AU - Américo, Carlos E.

AU - Stoffel, Tyler D.

AU - Poovathingal, Savio J.

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KW - Differential ablation

KW - Fluid-structure interactions

KW - Fluid-thermal interactions

KW - Marching windows

KW - Mesoscale coupling

KW - Voxel-to-surface map

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ISTHMUS: Interfacing Surface Triangles and voxels for Heterogeneous MUltiphysics Simulations

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

Access to Document

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