Flexible robotic welding cells have been established as an integral part of manufacturing. In order to plan the entire welding process in the design stage, mathematical modeling of the planning procedure has become very important. Both the geometric and non-geometric representations, such as the geometric description of workpieces, fixtures, and end-effectors and the planning of the welding process, are the key elements to success. Emphasis in this paper is fixture planning, in which an automated fixturing approach is examined to greatly increase workcell flexibility. A feature-based modeling approach is proposed to simulate the fixturing process in an automated welding cell.