Abstract: A Class of quartic DP blending functions with two shape parameters is presented, which is an extension of the cubic DP basis functions defined over the triangular domain; Properties of this new blending function are analyzed and the quartic DP parametric surface with two shape parameters over the triangular domain is defined. The surfaces' properties are similar with the cubic DP parametric surfaces. In particular, when the two shape parameters vanish, they degenerate to the cubic DP basis functions and the cubic DP parametric surfaces individually; by changing the two shape parameters, the shape of surface can be adjusted both wholly and locally in invariable control net.

Key words: computer application, surface design, DP surface, triangular domain, shape parameter