The advent of computer graphics and simulation software has strongly influenced the industrial design. Nowadays, when facing out the design of a new product or the re-design of an existing one it is of interest evaluating different design scenarios, by comparing physical and functional behaviors and product performances. Engineers are aimed to explore many and many "what-if" design scenarios for design optimization. The chapter focuses on two MatLAB®’s GUI applications, developed at University of Molise in collaboration with University of Naples (Italy): SVA-FEA (Statistical Variational Analysis & Finite Element Analysis) and PROMesh (PROcessing Mesh). The aim is to show how to provide advanced user interaction in several common tasks such as importing data, editing data, controlling FEA runs, visualizing results, and exporting results.