This paper discusses the usefulness of the Diana user-supplied subroutine mechanism for computational materials research at the Computational Materials Institute at Cornell University. We will present the implementation of an isotropic damage model as a test case. After a discussion of the various components of the model, we will present the implementation using the Diana usrmat routine. We show the versatility of Diana by using user-dened input items in the data le that allows us to develop a Diana version with a unique material model but with a standard Diana look-and-feel. This facilitates usage of the material model by students and other researchers.