Research in smart textiles and garments has mostly focused on integrating sensing technology. In order to make garments that are truly interactive it is also essential to develop technologies for actuating smart garments and textiles. We introduces ShapeTex, a thermal shape changing fabric that uses laminate thermal expansion to actuate textiles. We present the design process and rationale for ShapeTex; we explain the fabrication process we have developed for making ShapeTex accessible to fashion designers and interaction designers. Based on co-creation sessions with designers we discuss requirements derived from this material. Finally we present a number of concept prototypes created to explore and illustrate the potential applications of ShapeTex.