The researchers say their work could advance the development of such foldable objects as temporary emergency tents and wearable exoskeletons.
Image Credit: Morad Mirzajanzadeh.
Scientific Frontline: Extended "At a Glance" Summary: Reprogrammable Doubly Curved Origami Metamaterials
The Core Concept: A novel metamaterial design that transforms flat sheets into smooth, doubly curved 3D shells capable of switching from flexible to rigid load-bearing states on demand.
Key Distinction/Mechanism: Unlike traditional origami, which faces a structural trade-off between smooth curvature (resulting in soft structures) and rigid strength (resulting in jagged, faceted shapes), this method uses curved creases combined with embedded, adjustable cables (tendons). Modifying the tension of these cables allows the material’s stiffness to be reprogrammed without altering its overarching shape or base materials.
Origin/History: While origami-inspired structural design has previously enabled complex shape transformations and tunable stiffness in mechanical metamaterials (Wang et al., 2023), early rigid origami patterns frequently struggled to balance simple deployability with robust resistance against collapse under load (Zhai et al., 2018). Building on these foundations to overcome such limitations, McGill University researchers Damiano Pasini and Morad Mirzajanzadeh introduced this novel curved-crease paradigm, publishing their findings in February 2026.
Major Frameworks/Components:
- Curved-Crease Tiling: Geometric patterning that combines curved and straight creases to yield continuous, smooth surfaces (such as spheres or tori) rather than faceted geometric forms.
- Differential Geometry: Mathematical principles for developable surfaces, leveraged alongside numerical optimization, to precisely compute the necessary crease layouts for specific target 3D geometries.
- Tunable Internal Tendons: A mechanical integration using embedded cables to structurally lock the origami shell into a rigid state or release it into a highly flexible configuration.
Branch of Science: Mechanical Engineering, Materials Science, Applied Mathematics, and Structural Engineering.
Future Application: This technology paves the way for scalable, deployable objects such as temporary emergency habitats, wearable exoskeletons, morphing soft robots, smart fabrics, and deployable space structures.
Why It Matters: This advancement proves that tunable structural adaptability and heavy load-bearing capacity can be achieved through smart geometry alone, bypassing the need for complex, heavy materials or bulky external support systems in deployable technologies.
McGill University researchers have discovered a new way to fold flat sheets into smooth, curved shells that can switch from floppy and flexible to stiff and load-bearing on demand. By designing a special origami pattern and threading cable-like elements through it, they can control the material’s final three-dimensional shape and how rigid it becomes. The result, a “doubly curved lens box,” could advance the technology of such objects as temporary emergency tents, morphing robots, and smart fabrics, the researchers said.
“Existing foldable structures face a trade-off: if they are smooth and nicely curved, they tend to be soft and floppy; if they are strong and stiff, they usually look faceted, jagged, or uncomfortable, and their shape is hard to tune once built,” said Damiano Pasini, study coauthor and professor of mechanical engineering. “This is a major limitation for technologies such as wearable supports, medical implants, soft robots, and deployable space structures, which often need both smooth shapes and reliable strength to sturdily withstand externally applied forces.”
To overcome this limitation, the team designed an origami pattern with curved creases that folds into smooth, doubly curved surfaces, such as spheres or tori (doughnut shapes), and can then be “locked” into a rigid, load-bearing state. By adding internal tendons whose tension can be adjusted, the same structure can be reprogrammed to be ultrasoft or very stiff, without altering its shape or materials.
Adjustable Cables to Tune Rigidity
The new fold pattern combines curved and straight creases, allowing flat sheets to transform into continuous, smooth surfaces rather than the faceted forms typical of conventional origami.
Starting from a desired curved shape (such as a sphere, torus, or vase-like surface), the researchers used differential geometry—mathematical theories for origami tiling and developable surfaces—followed by numerical optimization to compute the exact crease pattern needed so that, once folded and locked, the origami shell would match the target geometry.
They next laser-cut and folded paperboard sheets into these patterns, assembled them into shells, and embedded thin cables (“tendons”) through specific points.
“By tightening or loosening the tendons, we measured how the stiffness changed and showed that the shells could go from saggy and flexible to rigid and resistant to twisting and bending,” Pasini said.
The researchers validated the findings with mechanics theory, rigid origami, and geometric simulations to confirm that the folding kinematics, or the object’s motions, are feasible. These simulations also confirmed that the surfaces would remain smooth and that the pattern could be scaled and tiled.
A “New Design Paradigm”
Pasini described the findings as a new design paradigm for origami metamaterials.
“Our approach opens new avenues for the design of deployable and adaptive load-bearing curved structures. Our findings challenge the idea that you need complex materials or external systems to get tunable stiffness, showing that smart geometry alone can do much of the work,” he said.
References:
- Wang, X., Qu, H., Li, X., Kuang, Y., Wang, H., & Guo, S. (2023). Multi-triangles cylindrical origami and inspired metamaterials with tunable stiffness and stretchable robotic arm. PNAS Nexus, 2. https://doi.org/10.1093/pnasnexus/pgad098 Cited by: 67
- Zhai, Z., Wang, Y., & Jiang, H. (2018). Origami-inspired, on-demand deployable and collapsible mechanical metamaterials with tunable stiffness. Proceedings of the National Academy of Sciences, 115, 2032–2037. https://doi.org/10.1073/pnas.1720171115 Cited by: 585
Funding: The study was funded by the Canada Research Chairs program, the Natural Sciences and Engineering Research Council of Canada, the McGill Engineering Doctoral Award, and the Fonds de recherche du Québec—Nature et technologies.
Published in journal: Nature Communications
Title: Smooth doubly curved origami shells with reprogrammable rigidity
Authors: Morad Mirzajanzadeh, and Damiano Pasini
Source/Credit: McGill University
Edited by: Scientific Frontline
Reference Number: eng052126_01