248 AutoCAD and Its Applications—Advanced 248 AutoCAD and Its Applications—Advanced In Figure 10-15, the game controller is to be redesigned with a new top shape. The model has been converted from a mesh model to a surface. In the original model (the mesh model), the top faces were deleted. The surface opening has eight continuous B C A Surface edge selected to create the patch surface A B Spline (guide curve) Surface edge selected to create the patch surface Figure 10-13. Creating a patch surface to close an opening in a surface model. A—The original model. The single surface edge indicated forms a closed loop and is selected to generate the patch surface. B—A patch surface created with the continuity set to G1 and the bulge magnitude set to 0.5. C—A patch surface created with the continuity set to G1 and the bulge magnitude set to 1. Figure 10-14. Using a guide curve to constrain the shape of a patch surface. A—The original model. The middle post has been added. The spline is drawn for use with the Guides option. B—The patch surface created after selecting the spline as the guide curve. Notice the resulting shape.