First developed by the architectural avante-garde in the early 20th century, the idea of the open plan was the result of a desire for greater transparency and flexibility in the design of interior environments. Essential to the functioning of the open plan in these early projects is the subtle articulation of differences between one part of the open interior and another. Later co-opted as an efficient means of achieving maximum density in office environments, the open plan as commonly practiced in the latter half of the 20th century resulted in undifferentiated, homogeneous Settings that failed to realize the original intentions of this architectural idea. Embedded information technology offers an opportunity to support the differentiation and legibility of the open plan by sensing and displaying aspects of the building's environmental conditions and patterns of use. We introduce two ongoing projects as examples of building interfaces that enhance the transparency of information in the building, using surfaces embedded in the building to reveal invisible attributes of the interior that can be used by inhabitants to better understand their environment.