The rational cubic function with three parameters has been extended to rational bi-cubic function to visualize the shape of regular convex surface data. The rational bi-cubic function involves six parameters in each rectangular patch. Data dependent constraints are derived on four of these parameters to visualize the shape of convex surface data while other two are free to refine the shape of surface at user choice. The developed constraints on parameters act as sufficient conditions for visualization of convex surface data. Moreover, computationally simple and less time consuming as compared to exiting techniques.