12. The apparatus of claim 11 , wherein: the cast indexing module is to merge face sets S i and S j when the distance between face sets S i and S j is sufficiently small.
12. The apparatus of claim 11 , wherein: the cast indexing module is to merge face sets S i and S j when the distance between face sets S i and S j is sufficiently small. 13. The apparatus of claim 12 , wherein the cast indexing module is to merge face sets S i and S j and bridging face sets {S b } when: the distance between S i and S j is not sufficiently small; and face sets S i and S j are bridged by the bridging face sets {S b }.