The morphogenetic patterning that generates three-dimensional (3D) tissues requires dynamic concerted rearrangements of individual cells with respect to each other.  We have developed microfabrication- and lithographic tissue engineering-based approaches to investigate the mechanical forces and downstream signaling responsible for generating the airways of the lung and the milk ducts of the mammary gland.  I will discuss how we combine these experimental techniques with computational models to uncover the physical forces that drive tissue development.