  In this paper, the problem of automating the pre-grasps generation for novel
3d objects has been discussed. The objects represented as cloud of 3D points
are split into parts and organized in a tree structure, where parts are
approximated by simple box primitives. Applying grasping only on the individual
object parts may miss a good grasp which involves a combination of parts. The
problem has been addressed by traversing the decomposition tree and checking
each node of the tree for possible pre-grasps against a set of conditions.
Further, a face mask has been introduced to encode the free and blocked faces
of the box primitives. Pre-grasps are generated only for the free faces.
Finally, the proposed method implemented on a set twenty-four household objects
and toys, where a grasp planner based on object slicing method has been used to
compute the contact-level grasp plan.
