In many branches of engineering, especially the aircraft industry, numerous geometric problems arise which present considerable difficulty to draughtsmen and designers. The object of this paper is to present methods which the writer has developed which enable any problem of the type under consideration to be rapidly solved. The majority of these problems arise in cases where, although sufficient data is provided to enable ordinary three view drawings of a particular part or assembly of parts to be made, angles and lengths have to be found which cannot be directly obtained from this three view drawing.