For Aristotelian scholars, matter is identified as the subject of change, while form is the boundary of matter. Design is a process of bringing about change. From a design perspective, material is what an entity is made from; form is what makes a thing what it is. Based on the principle, “form is the boundary of matter”, this paper proposes a Design by Material method, thereby addressing the knowledge gap of a systematic method for designing according to material. This method is predicated on the material specification as the first input in the design process. A formal model is built in which the material acts as a trigger and driver for the design process. The method is implemented by integrating computer-aided design (CAD) modelling and its design form. A design application is explained to demonstrate the relevance of the Design by Material method.