Drawing out information - lines of communication in technical illustration

The main graphical modes of information presentation, used in technical illustrations to show hidden detail, are identified and some historical precedents for them in the work of Leonardo Da Vinci are reviewed. Research into one particular aspect of graphic representation used in technical illustrations is reported. This concerns the deployment in hand-drawn images of different line thicknesses and their contribution to enhancing the interpretation of what is depicted. Whilst the use of varying line thicknesses has been formally incorporated into some documentation standards, it is not always observed in relevant domains. The case for and the process of replicating this line thickness code in computer-generated imagery, for use in multimedia technical documentation, are introduced.