A design application is configured to determine design problem geometry and design criteria associated with a design problem to be solved. Based on this information, the design application identifies one or more design approaches to creating a custom material having specific material attributes needed to solve the design problem. The design application then executes the design approaches to create material designs that reflect one or more custom materials. With these designs as input, a manufacturing machine may then construct physical instances of those custom materials. A given custom material may have a unique combination of material attributes potentially not found among existing materials. Additionally, a design fabricated from a custom material may better satisfy the design criteria than a design fabricated from a known material.