The increasing interest in materiality currently challenges the long existing traditions that consider visual thinking as the primary actor in design creativity. Shape grammars offer a formalism to represent visual reasoning in design, which is never purely limited to the visual aspects of design processes. Aiming to develop ways to explicitly include material manipulation in a computational formalism, we report on an ongoing exploration of how shape computation extends beyond abstract visual shapes to incorporate material shapes that have a physical existence. We present a materially informed process with shape rules and show that we can apply these rules creatively to explore the physical character of the material. (C) 2015 Elsevier Ltd. All rights reserved.