ABSTRACT: Block detection is one of the important steps in Discontinuous Deformation Analysis (DDA). This paper describes a new approach to the problem of geometrically defining polyhedral rock blocks created by the intersection of planar discontinuities in a rock mass. Using square matrices with integer elements and performing edge/face regularization, reduce the size of the matrices due to elimination of unnecessary faces, edges and vertices; speed and accuracy of block tracing operation will be increased. This algorithm is able to trace and identify all kind of blocks including convex and concave blocks formed by limited or unlimited fractures. The simplicity of the procedure makes it very attractive. The algorithm was programmed in C#.Net by over 8100 code lines; several examples are presented to show application of the algorithm in different situations.