Manas Bhargava
PhD student in the digital fabrication group at ISTA
Mesh Simplification For Unfolding
We present a computational approach for unfolding 3D shapes isometrically into the plane as a single patch without overlapping triangles. This is a hard, sometimes impossible, problem, which existing methods are forced to soften by allowing for map distortions or multiple patches. Instead, we propose a geometric relaxation of the problem: we modify the input shape until it admits an overlap-free unfolding. We achieve this by locally displacing vertices and collapsing edges, guided by the unfolding process. We validate our algorithm quantitatively and qualitatively on a large dataset of complex shapes and show its proficiency by fabricating real shapes from paper.
@article{https://doi.org/10.1111/cgf.15269,
author = {Bhargava, M. and Schreck, C. and Freire, M. and Hugron, P. A. and Lefebvre, S. and Sellán, S. and Bickel, B.},
title = {Mesh Simplification for Unfolding},
journal = {Computer Graphics Forum},
volume = {n/a},
number = {n/a},
pages = {e15269},
keywords = {fabrication, single patch unfolding, mesh simplification},
doi = {https://doi.org/10.1111/cgf.15269},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.15269},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/cgf.15269},
}
PCBend: Light Up Your 3D Shapes With Foldable Circuit Boards
ACM Transactions on Graphics (SIGGRAPH 2023)
We propose a computational design approach for covering a surface with individually addressable RGB LEDs, effectively forming a low-resolution surface screen. To achieve a low-cost and scalable approach, we propose creating designs from flat PCB panels bent in-place along the surface of a 3D printed core. Working with standard rigid PCBs enables the use of established PCB manufacturing services, allowing the fabrication of designs with several hundred LEDs. Our approach optimizes the PCB geometry for folding, and then jointly optimizes the LED packing, circuit and routing, solving a challenging layout problem under strict manufacturing requirements. Unlike paper, PCBs cannot bend beyond a certain point without breaking. Therefore, we introduce parametric cut patterns acting as hinges, designed to allow bending while remaining compact. To tackle the joint optimization of placement, circuit and routing, we propose a specialized algorithm that splits the global problem into one sub-problem per triangle, which is then individually solved. Our technique generates PCB blueprints in a completely automated way. After being fabricated by a PCB manufacturing service, the boards are bent and glued by the user onto the 3D printed support. We demonstrate our technique on a range of physical models and virtual examples, creating intricate surface light patterns from hundreds of LEDs.
@article{10.1145/3592411,
author = {Freire, Marco and Bhargava, Manas and Schreck, Camille and Hugron, Pierre-Alexandre and Bickel, Bernd and Lefebvre, Sylvain},
title = {PCBend: Light Up Your 3D Shapes With Foldable Circuit Boards},
year = {2023},
issue_date = {August 2023},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
volume = {42},
number = {4},
issn = {0730-0301},
url = {https://doi.org/10.1145/3592411},
doi = {10.1145/3592411},
journal = {ACM Trans. Graph.},
month = {jul},
articleno = {142},
numpages = {16},
keywords = {automated placement and routing, PCB design, PCB bending, 3D electronics}
}