Most additive manufacturing (AM) processes are layer-based with three linear motions in the X, Y, and Z axes. However, there are drawbacks associated with such limited motions, e.g., nonconformal material properties, stair-stepping effect, and limitations on building-around-inserts. Such drawbacks will limit AM to be used in more general applications. To enable 6-axis motions between a tool and a work piece, we investigated a Stewart mechanism and the feasibility of developing a low-cost 3D printer for the multidirectional fused deposition modeling (FDM) process. The technical challenges in developing such an AM system are discussed including the hardware design, motion planning and modeling, platform constraint checking, tool motion simulation, and platform calibration. Several test cases are performed to illustrate the capability of the developed multidirectional AM system. A discussion of future development on multidirectional AM systems is also given.