It may seem conceptually easy to draw a simple cross section or geological map using a CAD package. After all, with pencil and paper one just draws some boundary lines and fills the intervening areas with colour. In practice, novices will find this tricky with a CAD package. Each area to be coloured must be totally enclosed, and where areas are to be adjacent the boundary line must be duplicated for use in each enclosure. This involves much line duplication and editing, and the use of Layers. The following are some simple steps for newcomers to develop an appropriate methodology.