# Print-path design for inclined-plane robotic 3D printing of unreinforced concrete

Bhooshan S., Bhooshan V., Megens J., and Casucci T., Van Mele T. and Block P.
Design Modelling Symposium Berlin
2022

The paper details the toolkit for print-path synthesis and execution that was used in the physical realisation of an arched, bifurcating, unreinforced masonry footbridge spanning 16 metres, composed of 53 blocks of 3D-printed concrete. The printed concrete filaments of every block are placed in layers that are orthogonal to the expected, compressive force flow, resulting in the need for non-parallel, inclined print-path planes, thus also resulting in non-uniform print-layer heights. In addition, the bridge’s global structural logic of stereotomic masonry necessitated the precise coordination of the interface planes between blocks. Approximately 58 kilometres of print-path, distributed over 7800 inclined layers, were generated and coordinated such that the resulting print-paths meet printing-related criteria such as good spatial coherence, minimum and maximum layer thickness, infill patterns etc.

Bhooshan et al. (2018, 2020) describe a Function Representation based schema for inclined-plane print-path generation. We describe the full implementation and extension of the schema for practical and large-batch production. We also implement specific extensions to generate the infill print-paths typically needed in 3D concrete printing. Furthermore, we also describe the refinements incorporated into the print-processing toolkit, subsequent to the discoveries made during the physical realisation of the bridge.

Thus, the custom toolchain that was developed enables print-path synthesis, verification and generation of robotic instructions or so-called GCode. The toolchain and the constituent, standalone applets were designed to enable rapid iteration and refinement, whilst being free of external dependencies. Together, the toolkit provides a blueprint for real-time, printing-aware, interactive shape design. The fast print-processing enabled by the toolkit also makes it a suitable starting point for non-parallel ‘slicing’ of user-defined, input shapes.

BibTeX

@inproceedings{Bhooshan2022,
author    = "Bhooshan, S. and Bhooshan, V. and Megens, J. and and Casucci, T. and Van Mele, T. and Block, P.",
title     = "Print-path design for inclined-plane robotic 3D printing of unreinforced concrete",
booktitle = "Design Modelling Symposium Berlin ",
year      = "2022",
editor    = "",
volume    = "",
number    = "",
pages     = "",
publisher = "",
month     = "",
doi       = "",
note      = "accepted for publication",
}

Related publications

Architecture, Structures and Construction,2022.
ACM Symposium on Computational Fabrication (SCF) 2020,Cambridge,2020.
ROBARCH 2018 - Robotic Fabrication in Architecture, Art and Design 2018,: 98-109,SpringerZurich,2018 (September).
Humanizing Digital Reality - Proceedings of the Design Modelling Symposium 2017,: 493-508,SpringerParis,2018 (September).

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