BARCODE HOUSING SYSTEM is a computer-supported housing design and buildingsystem which adheres to the principles of open building in two ways: by distinguishingbetween support and infill systems, and by enabling the participation of different actorsin the processes of designing, building and using the dwellings. A rule-based generativesystem creates the housing units automatically and stores them in the system’sdatabase. Optimization techniques are used to assemble the units into housing buildingswhich can be constructed in multiple ways using industrial components stored in acatalogue. The different actors (architects, users, manufacturers, builders) participate atthe different stages of the design process, interacting with and through the system.