Scientists can now 3D print flat objects that automatically crawl, fold, or expand into new shapes without any motors or electronics.
March 31, 2026
Original Paper
Single-material 4D-printed shape-morphing structures via spatially patterned strain trapping
arXiv · 2603.27152
The Takeaway
Researchers developed a way to 'trap' mechanical tension directly into plastic as it is being printed. This allows a simple, flat-printed structure to transform into a functional, moving machine the moment it is triggered, effectively creating 'living' hardware.
From the abstract
A single-step, single-material 4D printing method is developed for programmable structures featuring spatially patterned strain trapping for one-way actuation. This approach enables fabrication on desktop fused filament fabrication 3D printers through a recently developed shape-memory strain programming method, Programming via Printing (PvP), which eliminates the need for secondary post-fabrication programming. Large (up to 50%) and spatially controlled trapped tensile strain programming is achi