  Modern 3D printers allow for the accurate placing of microscopic material
voxels, to form complex three-dimensional structures. The advancing
capabilities in multi-material printing, coupled with the discovery of
printable responsive materials, pave the way for the 3D printing of digital
materials, and for the 3D printing of shape-transforming structures, or 4D
printing. In this work, we leverage and combine these advancements to develop a
versatile methodology for crafting digitized 4D-printed shape-transforming
sheets. We 3D print digital responsive sheets, composed of active and passive
voxels that are meticulously positioned to form thin structures that can be
actuated on demand. This methodology enables us to encode the lateral geometry
and the reference curvature, separately and simultaneously. Our approach grants
us comprehensive control over the resulting shape, unlocking novel
opportunities in synthetic shape-morphing materials. Furthermore, it has the
potential to program anomalous mechanical properties and to be extended to
multi-material and metamaterial systems.
