This paper presents a study of the Computer Aided Design (CAD) needs for the Facilities Engineering Division (PENGD) of NASA Langley Research Center. PENGD currently has many more projects than resources. Government cuts and reductions in personnel promise to make the situation worse. PENGD needs to increase the throughput of its existing staff while also decreasing the product cycle of a project. The existing design scenario with PC based CAD is used as a baseline to evaluate possible improvements and cost savings by implementing workstation based CAD with feature-based solid modeling. A detailed case study is used to illustrate and compare the differences in designing with AutoCAD1 and ProlEngineer. Equivalent hourly engineering rates are calculated for each system based on a four year life cycle. The results of the case study and engineering rates are used to determine the actual cost of designing with both CAD systems. A costlbenefit analysis is used to determine the cost effectiveness of continued use of PC based CAD with complex design projects versus the purchase and integration of workstation based CAD. My findings conclude that projects with any degree of uncertainty benefit from workstation based CAD. Solid modeling provides a mechanism for thorough study which reduces modifications, rework, and schedule delays. The associative database greatly reduces the amount of time required to create and update drawings. As uncertainty increases, the savings from using workstation based CAD over PC based CAD also increases. / Master of Engineering