G2 continuity conditions for two adjacent B-spline surfaces

According to the results on the G¹ continuity conditions for two arbitrary degree B-spline surfaces with generally structured knots, this paper analyzes the property of the connecting functions of G¹ continuity first, then obtains the necessary and sufficient condition of G² continuity for two arbitrary degree B-spline surfaces with generally structured knots, meanwhile present a kind of sufficient conditions of G² continuity. In particular, this paper obtain the uniform smooth conditions for the above G² sufficient conditions. At the end, this paper give a constructing algorithm and examples for adjacent B-spline surfaces to be of G² continuity.