Material limitations and fabrication costs generally run at odds with the creativity of architectural design, producing a wealth of challenging computational geometry problems. We have developed an algorithm for solving an important class of fabrication constraints: those associated with planar construction materials such as glass or plywood. Starting with a complex curved input shape, defined as a NURBS or subdivision surface, we use an iterative clustering method to remesh the surface into planar panels following a cost function that is adjusted by the designer. We solved several challenging connectivity issues to ensure that the topology of the resulting mesh matches that of the input surface. The algorithm described in this paper has been implemented and developed in conjunction with an architectural design seminar. How the participants incorporated this tool into their design process was considered. Their important feedback led to key algorithmic and implementation insights as w...