Computational drawing support has the potential to improve design support in the early phase. Much work in this area is devoted to input of design information, manipulation, and presentation. Based on a review of current work, we note that among other things, digital drawing tools should be close to the conventions and techniques already used by architects. This is, in principle, possible by processing strokes in a more or less traditional sketch approach, or by offering specialised commands that provide a direct implementation of such conventions. The latter approach is covered by Structural Sketcher. A subset of drawing conventions developed earlier, called graphic units, is adopted within the system. In order to contribute to design support, the application of such graphic units should be fast and intuitive, and the definition of internal relationships should be quick and straightforward. For intuitive manipulation, Structural Sketcher incorporates the "paper and scissors" metaphor, and introduces a novel UI-concept called the KITE. To achieve an easy and fast maintenance of relationships, a graph based on anchor-points is built-up on the fly. Performance of the system has been tested on a quantitative and qualitative basis. The system shows the benefit that graphic units can bring to drawing support, and how these can be implemented. To conclude, limitations and further work are discussed.