Abstract: Data is generated for graphically displaying objects having surfaces defined by vertex locations, each having a particular intensity. The values of electrical signals that represent the coordinates of the vertex locations and a point normal used to obtain the intensities are controlled by programming a computer to generate electrical signals that represent coordinates of the vertices. The values of each of the coordinates is in terms of an equation having parameters "s" and "t". "t" is identified and kept constant at a first amount. The coordinate equations are factored to redefine them in terms of a first constant and a variable represented by "s". The equations are sequentially solved by substituting therein a predetermined series of values for "s" to control the values of the electrical signals so that certain of the signals represent ones of the coordinated that form a first row of the vertices.