Create Surface follows a similar approach to that taken in Clapp and Biondi (1994). The user picks a single surface from a 3-D depth migrated cube. The Create Surface algorithm constructs GOCAD format surfaces using two kinds of GOCAD object: plines (polygonal lines) and tsurf_t (surfaces). A closed pline is constructed from the outer two lines picked from a 3-D dataset. The remaining picked lines are loaded in as a set of vertices (vset), GOCAD's DSI algorithm is then applied to attract the surfaces to the picked points.
Project Manager takes as input a 3-D AVS field which contains the picked lines, obtained from the Create Line module. The 3-D field has dimensions of 3 by maximum number of points selected in a line by number lines. The points in the field represent the location of a single surface picked from a 3-D cube. The Surface Name parameter is used to indicate the name of the new surface to be created. If the surface already exists in the project, the user will be asked to confirm the replacement of the existing surface.
The N_Split widget allows the user to indicate the number of times to split the surface's triangles. Each split adds a point in the middle of each segment splitting one triangle into four triangles. With the additional points the DSI has more flexibility to smooth the surface. The additional flexibility is needed because the original picked points are set as immovable. The Number of Iteration widget allows the user specify the number of iterations of the DSI algorithm. Once the user has finished with the parameter specification, the write Project boolean should be selected.