Simulations can assist planners in optimizing their design and in minimizing its environmental impact. By adjusting the architecture according to simulation results, and running further simulations based on the adjusted design, an iterative process can help to increase the design quality. Up to now computing simulations have taken a long time, thus only a very limited number of iterations could be calculated. This project shows an approach that is close to a real time simulation. By dividing the simulation into smaller parts and running the software on clusters or vector supercomputers, first results are available within several seconds, and reasonable results in less than one minute. Besides the technical features, another focus is the easy accessibility of the simulation. Intuitive methods like a tangible user interface provide easy interaction methods for specialists as well as non specialists. The results of the simulation can be visualized and interacted with from the desktop or any kind of virtual environments. Further aspects like limitations of automatic grid generation, shape recognition and computation power are discussed.