Engineering sketches and drawings are the building blocks of technological design and production. These visual representations act as the means for organizing the design to production process, hence serving as a "social glue" both between individuals and between groups. The author discusses two main capacities such visual representations serve in facilitating distributed cognition in team design work As conscription devices, they enlist and organize group participation. As boundary objects, they facilitate the reading of alternative meanings by various groups involved in (...) the design process. The introduction of computer-aided design into this visual culture of engineering restructures relationships between workers in ways that can hamper the flexibility necessary for these crucial capacities to take place. The data are drawn from a study of the daily practices of engineers engaged in redesigning a turbine engine package. The method is participant observation. (shrink)