New materials are of high interest in additive manufacturing and in particular with 3D Printing. In this, talk we report on new properties and materials from Hierarchically porous thermoplastic polyurethane (TPU) that is 3D printed by direct viscous solution printing. The viscous materials are composed of powder mixture suspended in TPU polymer solution. In a 4D printing process, the printed objects undergo phase separation and chemical etching to generate three-level porous structure which transfers un-compressible plastics into super-elastic and lightweight elastic foam. Mechanical properties and porous structures are tunable through ink composition and computer design. This technique, for the first time, enables mold-free fabrication of TPU foam with complex 3D architectures. It is potentially a universal route to be applied to many other thermoplastic polymers for 4D printing of super compressible materials.