Computer generated solar envelopes in architecture

This paper offers a description of the development and potential uses of a tool that generates solar envelopes for architecture and planning. Work on the concept of the solar envelope was begun almost 30 years ago by Ralph Knowles. While the ideas proposed by Knowles have been widely published, practical application of the theories has been slow, partly because of the difficulties of visualising and calculating the solar envelope. This paper recapitulates the incremental steps from early hand-modelling techniques, and describes in detail the current interactive computer-based tool for solar envelope generation. The use of the computer program in the studio environment is described and compared with the original hand-based methods.