The present invention provides an RP system which can directly use hot melt polymers for fabricating porous 3D construct for cell culture and other biomedical applications based on a CAD design. To realize the direct use of polymer hot melt, the RP system uses a hot melt chamber which is mounted on a robotic dispensing ann or a XYZ motion control system. The hot melt chamber is equipped with a delivery mechanism to force the molten polymer passing through a nozzle. The extruded polymer thin filament deposits onto the positions according to the computer generated model, in a layer-by-layer fashion, similar to FDM. The present invention can use any type of thennal plastic polymer pellets, beads, particles, which are suitable for extrusion and injection molding, as well as composites of two or more different thermal plastic polymer blends, inorganic particle/thennal plastic composites.