An article of apparel is disclosed that includes a textile with at least one property that changes upon exposure to a physical stimulus. The textile has a modifiable structure formed from one or more yarns that exhibit a dimensional transformation upon exposure to the physical stimulus. The yarns have a first set of dimensions when unexposed to the physical stimulus, and the yarns have a second set of dimensions when exposed to the physical stimulus. The structure of the textile is modified by exposing the textile to the physical stimulus such that the yarns transform from the first set of dimensions to the second set of dimensions and change the property of the textile. Reinforcing structures, incisions, partial incisions, and coatings may also be utilized to enhance the textile structures