New MS-Windows-Based Educational Software for Teaching the Sunpath Diagram and Shading Mask Protractor

Abstract

The well-known versions of the sunpath diagrams and shading mask protractors that appear in the AIA's Architectural Graphics Standards are based on the equidistant projections and use a shading mask protractor developed by Olgyay and Olgyay at Princeton University in the 1950s. A designer using the AIA's Graphics Standards book, or other printed versions of the sunpath diagram must select the nearest latitude, make photocopies of the appropriate sunpath diagram and shading mask protractor, and then overlay the shading mask protractor upon the diagram in the proper orientation. The outline of the shading device is then transcribed upon the shading mask, aligned at the proper orientation for the facade in which the window is being analyzed, and placed on top of the sunpath diagram to determine if a point centered at the base of the window is exposed to direct sunlight. Obviously, teaching this process to architects and engineers is tedious and error-prone since the students must calculate several angles to ascertain whether or not a given shading device is going to work as planned and then painstakingly transcribe their calculations onto the printed sunpath diagram and shading mask protractor. This paper describes a new MS-Windows-based educational software package that has been developed to fast-track the learning and use of the sunpath diagram and shading mask protractor which is based on previously published equations for plotting the sunpath diagram and shading mask protractor. Examples will be provided that demonstrate some basic configurations of shading devices that are often misrepresented in the standard literature.