Given a point-based 3D computer graphics model which is defined by a point set P (P = {pi - R3}) and a desired reduced number of output samples Ns, the simplification approach finds a point set Ps which (i) satisfies |Ps| = Ns (|Ps| is the cardinality of Ps) and (ii) minimizes the difference of the corresponding surface Ss(defined by Ps) and the original surface S(defined by P). Although a number of previous approaches have been proposed for simplification, most of them (i) do not focus on point-based 3D models, (ii) do not consider efficiency, quality and generality together. In this paper, we introduce an adaptive simplification method (ASM) which is an efficient technique for simplifying point-based complex 3D model. ASM achieves low running time by clustering the points locally based on the preservation of geometric characteristics. Finally, we analyze the performance of ASM and show that it outperforms most of the current state-of-the-art methods in terms of efficiency, quality and generality.