Abstract
Recovering executable CAD programs from 3D meshes is challenging due to the compositional nature of CAD construction and the interaction between discrete modeling choices and continuous parameters. Many learning-based methods predict complete programs in a single pass and rely predominantly on sketch-extrude representations, limiting operation diversity and opportunities to correct geometric errors during reconstruction. We introduce StepCAD, a generative optimization approach that combines a state-conditioned CAD policy with geometry-guided search. Given an input mesh, the policy predicts construction actions conditioned on both target and intermediate geometry, and an IoU-guided tree search refines the resulting program through local edits. We also introduce ARCADE-1.5M, a large-scale dataset of 1.5M executable CAD programs spanning diverse operations, sequences with a maximum length of 150+ counted operations, and 12.5M intermediate state-action transitions. Experiments across multiple CAD reconstruction benchmarks show that StepCAD achieves state-of-the-art geometric reconstruction accuracy with consistently high validity, yielding up to 87.2% relative IoU improvement over the strongest evaluated baseline, with particularly large gains on complex shapes. Project page: https://ghadinehme.com/stepcad.github.io/
Keywords
Publication details
- Journal
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- Open access
- Green open access
Cite this article
APA 7
Nehme, G., & Ahmed, F. (2026). StepCAD: Mesh-to-CAD Code Generation via LLM Policy and Geometry-Guided Search. https://omanscience.com/en/articles/stepcad-mesh-to-cad-code-generation-via-llm-policy-and-geometry-guided-search
MLA 9
Nehme, Ghadi, and Faez Ahmed. "StepCAD: Mesh-to-CAD Code Generation via LLM Policy and Geometry-Guided Search." https://omanscience.com/en/articles/stepcad-mesh-to-cad-code-generation-via-llm-policy-and-geometry-guided-search.
Chicago (author–date)
Nehme, Ghadi, and Faez Ahmed. 2026. "StepCAD: Mesh-to-CAD Code Generation via LLM Policy and Geometry-Guided Search." https://omanscience.com/en/articles/stepcad-mesh-to-cad-code-generation-via-llm-policy-and-geometry-guided-search.
Harvard
Nehme, G. and Ahmed, F. (2026) 'StepCAD: Mesh-to-CAD Code Generation via LLM Policy and Geometry-Guided Search', Available at: https://omanscience.com/en/articles/stepcad-mesh-to-cad-code-generation-via-llm-policy-and-geometry-guided-search.
Vancouver
Nehme G, Ahmed F. StepCAD: Mesh-to-CAD Code Generation via LLM Policy and Geometry-Guided Search. https://omanscience.com/en/articles/stepcad-mesh-to-cad-code-generation-via-llm-policy-and-geometry-guided-search
IEEE
G. Nehme, and F. Ahmed, "StepCAD: Mesh-to-CAD Code Generation via LLM Policy and Geometry-Guided Search," https://omanscience.com/en/articles/stepcad-mesh-to-cad-code-generation-via-llm-policy-and-geometry-guided-search.