With the basic design established, the spaces are studied in turn and in greater detail. In this stage, new levels of questions are asked about interior and exterior finishes, window types, appliances, kitchen design, etc. The drawings are enlarged to show more detail and to allow for the refinement of the design. This is most often the longest phase in the design process, and when completed all the basic design decisions will have been made. Often during this phase, a model or series of study models are built to aid the process.