Direct 3D printing of baromorph structures

Wrapping a three-dimensional object with a sheet is a generally difficult task: if the object locally exhibits more than one curvature, the sheet has to locally change its metric in order to reproduce the target shape. In baromorph structures the local metric of a soft plate can be changed by inflating embedded channels. In the present work we show that it is possible to build efficiently these channels from a 3D printing technique refered to as direct ink writing. In addition to being able to print structures that produce in-plane stresses, this versitile printing technique allows us to preselect the direction of the curvature produced by the changes in local metric and not only to program the change in metric, but also the direction of the local curvature.