Background. Although three-dimensional computer models have been used to some degree in practice by a few large engineering and construction firms, there has been little research into how they can most effectively be used on construction sites and little investigation of their economic benefits. Much research is required if the use of three-dimensional CADD technology is to spread beyond the large industrial construction firms to become accepted practice in the building construction industry. In addition, feedback from research on construction sites is necessary to improve existing technology. The research described in this paper is fundamental research in the use of three-dimensional computer modeling as a means of technical communication in the construction process and in the use of such models in construction process simulation. The Project. In order to test hypotheses and codify the use of a three-dimensional model on a construction site, the new Center for Engineering and Physical Sciences Research (CEPSR) building under construction at Columbia University is being used as the test vehicle. The CEPSR is an eleven-story, 200,000 square foot reinforced concrete building. The building will house the central boiler plant for the University in its first four levels and research laboratories in its upper floors. The boiler plant was designed by Stone and Webster Engineering Corporation. The structure was designed by Helmuth, Obata and Kassabaum, Inc. All design was performed in two-dimensions. Some drawings were produced by CAD; others were hand-drawn. Phase I of the construction consisted of the foundation work. It was begun in February, 1989 and was completed on October 31, 1989. Phase II, the remainder of the building and boiler plant commenced in December, 1989 with a scheduled completion in the Fall of 1991. Turner Construction Company, Inc. is the construction manager for Phase II. The Phase II estimated construction cost is approximately $67 million.