In collaboration with Metropolitan Family Service (MFS), we conducted a three-year design-based research study to better understand how the characteristics of hands-on, home-based family engineering activities influence how preschool-age children and their parents engage in the engineering design process. Four themes emerged from the study: (1) Families used their imagination and activity narrative elements to set the design context, (2) Families evaluated and revised their solutions based on imagination-driven constraints, (3) Families creatively modified the design space, and (4) Imaginative