Ultimately designers aim is to achieve an integrated environment where - during the design process, including the early stages – the designer can generate a three-dimensional geometrical design, set up inter-related analysis and optimisation routines and receive meaningful feedback in realtime. Towards this ultimate goal Arup made a first feasible step. “3D Urbanism” is a research project aiming at bringing discreet quantitative analytical solutions (urban design, moving vehicles, moving people, acoustics, lighting and climate) into a unified Realtime interactive environment to demonstrate performance based design to designer, client and city planner.