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3D concrete printing (3DCP) structural components for construction assemblies are known for reduced material use and enhanced efficiency and design freedom. This article investigates the limitations in the geometrical and toolpath design of 3DCP structural components and presents an automated and comprehensive approach to their toolpath design and optimization. It exploits hierarchical geometric data structures and graph algorithms to achieve the following features: (1) By analyzing the overhang of toolpaths, the method offers quantitative criteria for determining the buildability of the components and predicting failure, thus assisting design decisions. (2) It provides toolpath offsetting and filleting methods that can enhance the dimensional accuracy of the print concerning layer line textures and overfills. (3) For branching and porous geometries, the method creates as-continuous-as-possible toolpaths with minimal stop-starts based on their topologies, thus reducing seam defects. (4) It converts the toolpath into efficient visualization meshes representing layer line textures and toolpath meshes compatible with finite elements analysis. The proposed method is implemented as a plug-in software within the environment of Grasshopper® for Rhino® to facilitate designers and engineers working with 3DCP. The effectiveness and versatility of the tool are demonstrated through the toolpath design and printing of four sets of examples. The tool reduces the number of toolpaths by 90% for a typical 80 mm nozzle and takes 0.21 s per meter of toolpath to slice, analyze overhang, generate continuous printing toolpaths, and visualize the print.
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This content will become publicly available on October 1, 2026
Surface-Toolpath Twins of Shell Components in 3D Concrete Printing for Optimized Buildability and Surface Quality
This paper directly links the abstract geometry of structural form-finding to the fabrication-aware design of discrete shells and spatial structures for 3D concrete printing through a bidirectional approach, where it creates surface-toolpath twins for the components, optimizing the buildability of the parts and their surface quality. The design-to-production process of efficient structural systems for 3D printing is often a top-down unidirectional process involving form-finding, segmentation, and slicing, where results face printability challenges due to incompatibility between the initial geometry and the printing system, as well as material constraints. We introduce surface-toolpath twins that can be interconverted and synchronized through efficient slicing and surface reconstruction algorithms to allow the combination of optimizations and modifications on either part of the twin in flexible orders. We provide two core methods for fabrication rationalization: (1) global buildability optimization on the surface mesh by normal-driven shape stylization and (2) local surface quality optimization on toolpath curves through intra-layer iterative adjustments. The result is a bidirectional design-to-production process where one can plug and play different form-finding results, assess and optimize their fabrication schemes, or leverage knowledge in fabrication design, model toolpath curves as sections, reconstruct surfaces, and merge them into form-finding and segmentation in an inverse way. The proposed framework enables the integration of form-finding expertise with fabrication-oriented design, allowing the realization of spatial shell structures with complex topologies or extreme geometrical features through 3D concrete printing.
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- PAR ID:
- 10651390
- Editor(s):
- Gerardo_Oliva, J; Ignacio_del_Cueto, J; Drago, E
- Publisher / Repository:
- Proceedings of the IASS Annual Symposium 2025
- Date Published:
- Subject(s) / Keyword(s):
- 3D concrete printing, continuous shells, toolpath design, shape stylization, surface reconstruction
- Format(s):
- Medium: X
- Location:
- Mexico City, Mexico
- Sponsoring Org:
- National Science Foundation
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