Copyright Goodheart-Willcox Co., Inc. Chapter 7 Sweeps and Lofts 155 the profi le will be moved so it is perpendicular to the path. If you select No, the profi le is kept in the same position relative to the path as it is swept. The position of the shape determines the alignment. This will not work if the profi le and path are coplanar. Changing the Base Point The base point is the location on the shape that will be moved along the path to create the sweep. By default, if the shape intersects the path, the profi le is swept along the path at the point of intersection. If the shape does not intersect the path, the default base point depends on the type of object being swept. When lines and arcs are swept, the default base point is their midpoint. Open polylines have a default base point at the midpoint of their total length. The base point can be any point on the shape or anywhere in the drawing. See Figure 7-4. To change the base point, use the Base point option of the SWEEP command. When the command is initiated, select the profi le and press [Enter]. Before selecting the path, enter the Base point option. Next, pick the new base point. It does not have to be on an existing object. Once the new base point is selected, pick the path to create the sweep. A B C A B C Figure 7-3. A—The profile and path for the sweep. B—By default, the profile is aligned perpendicular to the path when swept. C—Using the Alignment option, the profile can be swept so it is not perpendicular to the path. Figure 7-4. A—The profile and path for the sweep. B—The sweep is created with the default base point. C—The end of the path is selected as the base point. Notice the difference in this sweep and the one shown in B.