Instantly generating Delaunay Triangulation on scattered point set is the base of developing 3D visual route design system, the study on the method of instantly building Delaunay triangulation is of important academic meanings and practical values, an algorithm for instantly creating triangulation is presented in the paper. First, use several points to create an initial triangular mesh which boundary is a convex polygon. Secondly, connect the rest points with the existed mesh to create new mesh, if a point locates into a triangle, link the point and the vertices of the triangle to update the mesh; if a point is out of the existed mesh, find the two support lines from the point to the boundary convex polygon, the two lines and the boundaries create a polygon, cut the polygon into triangles to form new mesh. Finally, the triangular mesh is changed into Delaunay triangulation by local optimization procedure. The algorithm is suitable for instantly generating triangulation because it can start to create triangles when partial points given; moreover, the algorithm utilizes subareas to control the vertices of convex hull so that the range which support points locate in can be predefined when searching support lines, the work of searching support points can be reduced and the speed of triangulation creating is raised.
