An article of apparel is disclosed that is at least partially formed from a material element having a substrate and a plurality of projections. The substrate has a first surface and an opposite second surface. The projections extend from the first surface of the substrate, and the projections each have terminal ends located opposite the substrate. The material element has a first permeability when the first surface has a convex configuration, and the material element has a second permeability when the first surface has a concave configuration, the first permeability being greater than the second permeability. The apparel may be reversible such that either the first surface or the second surface of the substrate faces outward.