Direct 2D-to-3D transformation of pen drawings.

Pen drawing is a method that allows simple, inexpensive, and intuitive two-dimensional (2D) fabrication. To integrate such advantages of pen drawing in fabricating 3D objects, we developed a 3D fabrication technology that can directly transform pen-drawn 2D precursors into 3D geometries. 2D-to-3D transformation of pen drawings is facilitated by surface tension-driven capillary peeling and floating of dried ink film when the drawing is dipped into an aqueous monomer solution. Selective control of the floating and anchoring parts of a 2D precursor allowed the 2D drawing to transform into the designed 3D structure. The transformed 3D geometry can then be fixed by structural reinforcement using surface-initiated polymerization. By transforming simple pen-drawn 2D structures into complex 3D structures, our approach enables freestyle rapid prototyping via pen drawing, as well as mass production of 3D objects via roll-to-roll processing.