Self-Refining Topology Optimization via an LLM-Based Multi-Agent Framework
Pith reviewed 2026-05-25 03:04 UTC · model grok-4.3
The pith
A system of six LLM agents automates topology optimization by iteratively refining setups, code, and designs through collaboration.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
TopOptAgents consists of six LLM-based agents collaborating through iterative self-refinement cycles spanning problem formulation, validation, code generation and execution, and quality assessment of the optimized structure. This process enables error correction and progressive improvement of both the optimization setup and resulting design. The framework is demonstrated on optimization problems selected to cover a range of settings that differ in their literature coverage and numerical characteristics. The benefits of iterative self-refinement are found to be particularly pronounced for problem classes where the pretrained language model has limited prior exposure, such as formulations with
What carries the argument
TopOptAgents, the six-agent LLM system that runs repeated self-refinement cycles across formulation, validation, coding, execution, and design evaluation.
If this is right
- Expert decisions about parameters and feasibility become part of the automated loop instead of external interruptions.
- Self-refinement yields the largest gains on problems whose formulations and code examples are rare in training data.
- The range of topology optimization tasks that LLM automation can complete reliably expands beyond what single models achieve.
- Converged designs emerge from the process even when initial agent outputs contain inconsistencies or invalid code.
Where Pith is reading between the lines
- The same agent-division and refinement pattern could transfer to other iterative engineering tasks such as structural sizing or fluid-device layout.
- If the collaboration pattern holds across models, it offers a route to reduce dependence on hand-tuned commercial solvers for standard problems.
- Extending the agents to include explicit manufacturing or cost checks would test whether the loop can absorb constraints left out of the base optimization.
- Measuring whether refinement steps actually decrease error metrics over cycles would give a direct check on whether the process improves rather than stabilizes.
Load-bearing premise
That the back-and-forth among the six agents produces genuine error correction and steady improvement rather than simply repeating or compounding the base model's mistakes.
What would settle it
A side-by-side test on the same set of low-literature topology problems measuring the fraction of runs that reach converged, physically feasible designs for the multi-agent system versus a single LLM.
Figures
read the original abstract
Topology optimization is a widely used design method that produces optimized material distributions for prescribed objectives and constraints through well-established numerical algorithms. Throughout the workflow, engineers make a series of decisions ranging from setting and adjusting numerical parameters to assessing whether the converged design meets considerations beyond those explicitly included in the optimization problem, such as physical feasibility. These decisions, which draw on domain expertise, interfere with the autonomous design process. To address this difficulty, this study presents TopOptAgents, a multi-agent system for automating not only the design process but also decision-making during the key stages of the topology optimization process. TopOptAgents consists of six LLM-based agents collaborating through iterative self-refinement cycles spanning problem formulation, validation, code generation and execution, and quality assessment of the optimized structure. This process enables error correction and progressive improvement of both the optimization setup and resulting design. The framework is demonstrated on optimization problems selected to cover a range of settings that differ in their literature coverage and numerical characteristics The benefits of iterative self-refinement are found to be particularly pronounced for problem classes where the pretrained language model has limited prior exposure, such as formulations whose literature and open-source implementations are comparatively sparse. In such cases, the proposed framework reliably produces converged designs where a single state-of-the-art LLM struggles, suggesting that self-refinement broadens the range of topology optimization problems that LLM-based automation can reliably address.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript introduces TopOptAgents, a multi-agent framework of six LLM-based agents that collaborate via iterative self-refinement cycles to automate the full topology optimization workflow, encompassing problem formulation, validation, code generation/execution, and post-optimization quality assessment. It claims that this process enables error correction and progressive improvement, reliably yielding converged designs on selected problems (chosen for varying literature coverage and numerical characteristics) where a single state-of-the-art LLM fails, with benefits most pronounced on sparse-literature formulations.
Significance. If substantiated, the work would demonstrate a practical route for extending LLM reliability in engineering design automation beyond base-model limits on low-exposure problem classes, potentially reducing reliance on human expertise for parameter tuning and feasibility checks in topology optimization.
major comments (2)
- [Demonstration and results (abstract and implied experimental section)] The central claim that iterative collaboration among the six agents produces genuine error correction (rather than variance from repeated sampling) is load-bearing yet unsupported by any ablation that disables the refinement cycle while holding total token budget or LLM-call count fixed; the abstract's demonstration on sparse problems therefore cannot isolate the claimed mechanism.
- [Demonstration and results (abstract and implied experimental section)] No per-iteration error-type logs, success-rate statistics over repeated trials, or baseline comparisons with equivalent compute (e.g., single-LLM retries) are described, leaving open the possibility that observed convergence on low-literature-coverage cases arises from base-model stochasticity rather than cross-agent correction of invalid constraints or mesh errors.
Simulated Author's Rebuttal
We thank the referee for the constructive critique of the experimental support for the self-refinement mechanism. We agree that the current manuscript does not provide the controlled comparisons needed to isolate iterative cross-agent correction from base-model stochasticity, and we will revise the paper to include the requested analyses.
read point-by-point responses
-
Referee: The central claim that iterative collaboration among the six agents produces genuine error correction (rather than variance from repeated sampling) is load-bearing yet unsupported by any ablation that disables the refinement cycle while holding total token budget or LLM-call count fixed; the abstract's demonstration on sparse problems therefore cannot isolate the claimed mechanism.
Authors: We agree that an ablation holding total token budget and LLM-call count fixed is required to separate the contribution of the multi-agent refinement loop from repeated independent sampling. The manuscript currently compares the framework against single-LLM attempts but does not enforce compute parity in this way. In revision we will add this ablation on the sparse-literature problems, reporting success rates for the full TopOptAgents loop versus an equivalent-budget regime of independent single-LLM generations (with the same total calls and tokens). revision: yes
-
Referee: No per-iteration error-type logs, success-rate statistics over repeated trials, or baseline comparisons with equivalent compute (e.g., single-LLM retries) are described, leaving open the possibility that observed convergence on low-literature-coverage cases arises from base-model stochasticity rather than cross-agent correction of invalid constraints or mesh errors.
Authors: We acknowledge that the manuscript lacks per-iteration error logs, multi-trial success statistics, and matched-compute single-LLM baselines. These omissions leave the mechanism under-supported. In the revised version we will include (i) logs classifying error types corrected at each iteration, (ii) success-rate tables over at least five independent trials per problem, and (iii) direct comparisons against single-LLM retry baselines that consume the same total token or call budget. revision: yes
Circularity Check
No circularity: empirical system demonstration with no derivations or self-referential loops
full rationale
The paper describes a multi-agent LLM framework (TopOptAgents) for topology optimization and reports empirical results on selected problems. No equations, parameters, or mathematical derivations are present in the provided text. Claims rest on observed performance differences between single-LLM and multi-agent setups rather than any prediction or result that reduces to its own inputs by construction. Self-citations, if present, are not load-bearing for any derivation chain. This is a standard non-circular empirical presentation.
Axiom & Free-Parameter Ledger
Reference graph
Works this paper leans on
-
[1]
J. D. Deaton, R. V. Grandhi, A survey of structural and multidisciplinary continuum topology optimization: post 2000, Structural and multidisciplinary optimization 49 (1) (2014) 1–38
work page 2000
-
[2]
O. Sigmund, K. Maute, Topology optimization approaches: A comparative review, Structural and multidisciplinary optimization 48 (6) (2013) 1031–1055
work page 2013
- [3]
-
[4]
R. Yang, A. Chahande, Automotive applications of topology optimization, Structural optimization 9 (3) (1995) 245–249
work page 1995
-
[5]
N. M. Patel, B.-S. Kang, J. E. Renaud, A. Tovar, Crashworthiness design using topology optimiza- tion (2009)
work page 2009
-
[6]
C. Lundgaard, J. Alexandersen, M. Zhou, C. S. Andreasen, O. Sigmund, Revisiting density-based topology optimization for fluid-structure-interaction problems, Structural and Multidisciplinary Op- timization 58 (3) (2018) 969–995
work page 2018
-
[7]
M. Pietropaoli, F. Montomoli, A. Gaymann, Three-dimensional fluid topology optimization for heat transfer, Structural and Multidisciplinary Optimization 59 (3) (2019) 801–812
work page 2019
-
[8]
M. E. Lynch, S. Sarkar, K. Maute, Machine learning to aid tuning of numerical parameters in topology optimization, Journal of Mechanical Design 141 (11) (2019) 114502
work page 2019
-
[9]
S. Zhang, J. A. Norato, Finding better local optima in topology optimization via tunneling, in: Inter- national Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Vol. 51760, American Society of Mechanical Engineers, 2018, p. V02BT03A014
work page 2018
-
[10]
D. Ha, J. Carstensen, Automatic hyperparameter tuning of topology optimization algorithms using surrogate optimization: D. ha, j. carstensen, Structural and Multidisciplinary Optimization 67 (9) (2024) 157
work page 2024
-
[11]
M. Zhou, Y. Shyy, H. Thomas, Checkerboard and minimum member size control in topology opti- mization, Structural and Multidisciplinary Optimization 21 (2) (2001) 152–158
work page 2001
-
[12]
W. S. Song, H. Park, J. Park, S. Min, Adaptive beta update scheme in heaviside projection method of topology optimization, Computer Methods in Applied Mechanics and Engineering 453 (2026) 118805
work page 2026
-
[13]
P. Dunning, F. Wein, Automatic projection parameter increase for three-field density-based topology optimization, Structural and multidisciplinary optimization 68 (2) (2025) 33
work page 2025
-
[14]
W. X. Zhao, K. Zhou, J. Li, T. Tang, X. Wang, Y. Hou, Y. Min, B. Zhang, J. Zhang, Z. Dong, et al., A survey of large language models, arXiv preprint arXiv:2303.18223 1 (2) (2023) 1–124
work page internal anchor Pith review Pith/arXiv arXiv 2023
-
[15]
J. Gu, X. Jiang, Z. Shi, H. Tan, X. Zhai, C. Xu, W. Li, Y. Shen, S. Ma, H. Liu, et al., A survey on llm-as-a-judge, The Innovation (2024)
work page 2024
-
[16]
A. Zhao, D. Huang, Q. Xu, M. Lin, Y.-J. Liu, G. Huang, Expel: Llm agents are experiential learners, in: Proceedings of the AAAI Conference on Artificial Intelligence, Vol. 38, 2024, pp. 19632–19642
work page 2024
-
[17]
L. Wang, C. Ma, X. Feng, Z. Zhang, H. Yang, J. Zhang, Z. Chen, J. Tang, X. Chen, Y. Lin, et al., A survey on large language model based autonomous agents, Frontiers of Computer Science 18 (6) (2024) 186345
work page 2024
-
[18]
M. J. Buehler, Melm, a generative pretrained language modeling framework that solves forward and inverse mechanics problems, Journal of the Mechanics and Physics of Solids 181 (2023) 105454
work page 2023
-
[19]
M. J. Buehler, Mechgpt, a language-based strategy for mechanics and materials modeling that connects knowledge across scales, disciplines, and modalities, Applied Mechanics Reviews 76 (2) (2024) 021001
work page 2024
- [20]
-
[21]
T. Guo, X. Chen, Y. Wang, R. Chang, S. Pei, N. V. Chawla, O. Wiest, X. Zhang, Large language model based multi-agents: A survey of progress and challenges, arXiv preprint arXiv:2402.01680 (2024)
work page internal anchor Pith review Pith/arXiv arXiv 2024
- [22]
- [23]
-
[24]
B. Ni, M. J. Buehler, Mechagents: Large language model multi-agent collaborations can solve mechanics problems, generate new data, and integrate knowledge, Extreme Mechanics Letters 67 (2024) 102131
work page 2024
-
[25]
D. Park, H. Moon, S. Ryu, A self-correcting multi-agent llm framework for language-based physics simulation and explanation, npj Artificial Intelligence 2 (1) (2026) 10
work page 2026
-
[26]
R. Deotale, A. Srinivasan, M. Golestanian, Y. Tian, T. Zhang, P. Vlachos, H. Gomez, All-fem: Agentic large language models fine-tuned for finite element methods, Computer Methods in Applied Mechanics and Engineering 457 (2026) 118985
work page 2026
-
[27]
P. Chen, Y. Cai, Z. Zhou, J. Yao, J. Li, W. You, L. Sun, An llm-based multi-agent system to assist early-stage product design and evaluation, Journal of Engineering Design (2026) 1–36
work page 2026
- [28]
-
[29]
L. Chen, H. Zuo, Z. Cai, Y. Yin, Y. Zhang, L. Sun, P. Childs, B. Wang, Toward controllable gener- ative design: A conceptual design generation approach leveraging the function–behavior–structure ontology and large language models, Journal of Mechanical Design 146 (12) (2024) 121401
work page 2024
- [30]
-
[31]
F. Liu, X. Zeng, H. Liu, Towards multimodal data-driven scientific discovery powered by llm agents, in: The Fourteenth International Conference on Learning Representations, 2026
work page 2026
-
[32]
AgentCoder: Multi-Agent-based Code Generation with Iterative Testing and Optimisation
D. Huang, J. M. Zhang, M. Luck, Q. Bu, Y. Qing, H. Cui, Agentcoder: Multi-agent-based code generation with iterative testing and optimisation, arXiv preprint arXiv:2312.13010 (2023)
work page internal anchor Pith review Pith/arXiv arXiv 2023
-
[33]
O. Sigmund, Topology optimization: a tool for the tailoring of structures and materials, Philosophi- cal Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences 358 (1765) (2000) 211–227
work page 2000
-
[34]
O. Sigmund, A 99 line topology optimization code written in matlab, Structural and multidisci- plinary optimization 21 (2) (2001) 120–127
work page 2001
-
[35]
S. Rojas-Labanda, O. Sigmund, M. Stolpe, A short numerical study on the optimization methods influence on topology optimization, Structural and Multidisciplinary Optimization 56 (6) (2017) 1603–1612
work page 2017
-
[36]
K. Liu, A. Tovar, An efficient 3d topology optimization code written in matlab, Structural and multidisciplinary optimization 50 (6) (2014) 1175–1196
work page 2014
-
[37]
S. Rojas-Labanda, M. Stolpe, Benchmarking optimization solvers for structural topology optimiza- tion, Structural and Multidisciplinary Optimization 52 (3) (2015) 527–547
work page 2015
-
[38]
O. Sigmund, J. Petersson, Numerical instabilities in topology optimization: a survey on procedures dealing with checkerboards, mesh-dependencies and local minima, Structural optimization 16 (1) (1998) 68–75
work page 1998
-
[39]
B. S. Lazarov, O. Sigmund, Filters in topology optimization based on helmholtz-type differential equations, International journal for numerical methods in engineering 86 (6) (2011) 765–781
work page 2011
-
[40]
F. Wang, B. S. Lazarov, O. Sigmund, On projection methods, convergence and robust formulations in topology optimization, Structural and multidisciplinary optimization 43 (6) (2011) 767–784
work page 2011
-
[41]
J. K. Guest, A. Asadpoure, S.-H. Ha, Eliminating beta-continuation from heaviside projection and density filter algorithms, Structural and Multidisciplinary Optimization 44 (4) (2011) 443–453
work page 2011
-
[42]
M. Oshin, N. Campos, Learning LangChain, " O’Reilly Media, Inc.", 2025. 27
work page 2025
-
[43]
E. Andreassen, A. Clausen, M. Schevenels, B. S. Lazarov, O. Sigmund, Efficient topology optimiza- tion in matlab using 88 lines of code, Structural and Multidisciplinary Optimization 43 (1) (2011) 1–16
work page 2011
-
[44]
Y. Wang, X. Li, K. Long, P. Wei, Open-source codes of topology optimization: A summary for beginners to start their research, Computer Modeling in Engineering & Sciences 137 (1) (2023) 1–34
work page 2023
-
[45]
E. Holmberg, B. Torstenfelt, A. Klarbring, Stress constrained topology optimization, Structural and Multidisciplinary Optimization 48 (1) (2013) 33–47
work page 2013
-
[46]
D. M. De Leon, J. Alexandersen, J. S. O. Fonseca, O. Sigmund, Stress-constrained topology op- timization for compliant mechanism design, Structural and Multidisciplinary Optimization 52 (5) (2015) 929–943
work page 2015
-
[47]
C. Le, J. Norato, T. Bruns, C. Ha, D. Tortorelli, Stress-based topology optimization for continua, Structural and Multidisciplinary Optimization 41 (4) (2010) 605–620
work page 2010
-
[48]
S. Park, B. Goh, H. Chung, Topology optimization with material point method: investigation into the design sensitivity and the effect of shape functions, Engineering with Computers 41 (5) (2025) 3099–3116
work page 2025
- [49]
- [50]
-
[51]
E. Wu, G. Kenway, C. A. Mader, J. Jasa, J. R. ra Martins, pyoptsparse: A python framework for large-scale constrained nonlinear optimization of sparse systems, Journal of Open Source Software 5 (54) (2020) 2564
work page 2020
-
[52]
C. Li, J. Flanigan, Task contamination: Language models may not be few-shot anymore, in: Pro- ceedings of the AAAI Conference on Artificial Intelligence, Vol. 38, 2024, pp. 18471–18480
work page 2024
-
[53]
M. Riddell, A. Ni, A. Cohan, Quantifying contamination in evaluating code generation capabilities of language models, in: Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), 2024, pp. 14116–14137
work page 2024
-
[54]
O. Sigmund, On benchmarking and good scientific practise in topology optimization, Structural and Multidisciplinary Optimization 65 (11) (2022) 315
work page 2022
-
[55]
P. Duysinx, M. P. Bendsøe, Topology optimization of continuum structures with local stress con- straints, International journal for numerical methods in engineering 43 (8) (1998) 1453–1478
work page 1998
-
[56]
P. E. Gill, W. Murray, M. A. Saunders, Snopt: An sqp algorithm for large-scale constrained opti- mization, SIAM review 47 (1) (2005) 99–131
work page 2005
-
[57]
V. Prabhakar, M. A. Islam, A. Atanas, Y.-T. Wang, J. Han, A. Jhunjhunwala, R. Apte, R. Clark, K. Xu, Z. Wang, et al., Omniscience: A domain-specialized llm for scientific reasoning and discovery, arXiv preprint arXiv:2503.17604 (2025)
- [58]
- [59]
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.