Systems and methods for creating custom-fit prosthetic devices, orthotic devices, and related medical devices via three-dimensional printing (3D printing) or additive manufacturing techniques are described. Through the described systems and methods, a residual limb or other body part of a patient is scanned and analyzed to determine measurements and characteristics of the residual limb. The measurements and characteristics of the residual limb are used to design a customized device for the residual limb. The customized device uses multiple different materials. For example, the customized device may use a first material for a frame and a second material for a liner, wherein the first material is more rigid than the second material. The customized device is fabricated using a three-dimensional printer that is capable of printing and bonding multiple different materials at the same time.