Abstract: A CAD system having a plurality of clients connected by a network enables simulations to be run that reflect design information from other client CADs. A server 100 causes a computing unit 101 to reflect in a three-dimensional model generated based on design according to any given client 110-140 design data according to any other client 110-140. Then, using that three-dimensional model, the server carries out an operating simulation and transmits the simulation results to the requesting client. The client that receives the simulation results from the server 100 then displays those simulation results on a design screen.