Abstract: Active fabrics can be created by combining active and passive materials. Active materials with shape memory or other actuation characteristics can generate compression or dynamic fit, and the level of compression and/or change in fit can be determined by setting a knit index, wire diameter, and garment ease, or fit in relation to the body. Maximum compression can be set not only by varying physical properties of the knit structure but by built-in circuit breaking technologies, or by segmentation and control of the garment by a controller. In some embodiments, additive manufacturing can be combined with traditional textile equipment (e.g., circular knitting machine). Uniquely functional or active textiles can be made from additively manufactured, heterogeneous filaments. Yarn-like filament with varying properties (such as elasticity, stiffness, conductivity, activation, or surface properties) can be additively manufactured.