Sketch design: Now that the existing situation has been established, the aesthetic and regulatory preconditions are known and the project principles have also been sufficiently defined, the first step of the so-called design phases, namely the sketch design, can be started. The draft design will provide insight into the spatial and functional design of the future building. At the end of this phase, the draft design will be presented to the client. For smaller projects, the sketch design phase can be directly combined with the next phase: the preliminary design.