Parametric techniques herald an age of predictive design. Results from simulations, analytical data and design performance criteria directly influence or drive architecture. However, this is still a relatively passive design approach: parameters go in, design comes out. Al Fisher explains the work of Buro Happold's SMART Solutions team on developing real-time simulations where the analysis is persistent within the model. Lightweight, mobile versions of tools traditionally reserved for detailed analysis can form the early conceptual stages of design. Interactive models can be tweaked and manipulated, with the live feedback of results providing a link to the materiality of the design. Through a responsive approach, hybrid design can be achieved that blends performance with design intent. Copyright © 2012 John Wiley & Sons, Ltd.