Abstract: An orthopedic precast comprises a knitted shell portion and a knitted flexible portion. The precast is positioned about a limb or other mold, and heat or other hardening agent is used to harden the shell portion, while retaining flexibility in the flexible portion. Contemplated hardening agents include light, heat, and chemical polymerizing agents. In some embodiments the shell portion includes threads or yarns comprising a thermoplastic, which is then hardened by heating the thermoplastic sufficiently to at least partially melt, and thereby fuse together some of the threads or yarns, and then cooling to ambient temperature. In other embodiments, the precast is contained in a bag or other airtight container, along with a self-heating composition that is triggered to release heat upon contact with oxygen. In still other embodiments, the precast includes a prepolymer of other polymerizable composition, which is polymerized by effective application of light, heat, and/or chemical agent(s).