  We present a method for fabricating general models with multi-directional 3D
printing systems by printing different model regions along with different
directions. The core of our method is a support-effective volume decomposition
algorithm that minimizes the area of the regions with large overhangs. A
beam-guided searching algorithm with manufacturing constraints determines the
optimal volume decomposition, which is represented by a sequence of clipping
planes. While current approaches require manually assembling separate
components into a final model, our algorithm allows for directly printing the
final model in a single pass. It can also be applied to models with loops and
handles. A supplementary algorithm generates special supporting structures for
models where supporting structures for large overhangs cannot be eliminated. We
verify the effectiveness of our method using two hardware systems: a
Cartesian-motion based system and an angular-motion based system. A variety of
3D models have been successfully fabricated on these systems.
