Final answer:
Bill uses Computer-Aided Design (CAD) applications like ArchiCAD to create 3-dimensional digital models of buildings for his architectural projects.
Step-by-step explanation:
Bill is working on an architectural project and he uses Computer-Aided Design (CAD) applications, such as ArchiCAD, to create digital replicas of buildings. The invention of CAD in 1961 revolutionized architectural design with its realistic representations, speed, accuracy, and affordability.
Today's sophisticated CAD programs allow architects to design, draw final plans, and make intricate 3-dimensional models viewable from different angles without the need for physical models. Virtual tours can also be generated to offer exact views of the architectural design, helping clients visualize the final product more effectively.