The design community has lost a great thinker. One whose ideas provided foundations for the very work we are engaged in on a daily basis. Several of us on the Revit team were touched directly by Bill and his work as we started on the paths that lead us here. In the early day of Revit, we met with him several times to discuss the feasibility of our effort. He was most encouraging. As he moved on, he never lost that clarity that allowed him to be thinking 10 years ahead of the tools and paradigms used in practice. Bill’s passing will be a loss to all who are involved in the community of design.