153 Copyright Goodheart-Willcox Co., Inc. Learning Objectives After completing this chapter, you will be able to: ✓ Sweep shapes along a 2D or 3D path to create a solid or surface object. ✓ Create 3D solid or surface objects by lofting a series of cross sections. In the previous chapter, you learned about extruded solids and surfaces. Sweeps and lofts are similar to extrusions. In fact, an extrusion is really just a type of sweep. A sweep is an object created by extruding a single profi le along a path object. Sweeping an open shape along the path results in a surface object. If a closed shape is swept, a solid or surface object can be created. A loft is an object created by extruding between two or more 2D profi les. The shape of the loft object blends from one cross-sectional profi le to the next. The profi les can control the loft, or the loft can be controlled by one path or multiple guide curves. As with a sweep, open shapes result in surfaces and closed shapes give you solids. Open and closed shapes cannot be used together in the same loft. Creating Swept Surfaces Creating Swept Surfaces and Solids and Solids The SWEEP command is used to create swept surfaces and solids. The command requires at least two objects: • Shape to be swept. • 2D or 3D shape to be used as the sweep path. The profi le can be aligned with the path, you can specify the base point, a scale factor can be applied, and the profi le can be twisted as it is swept. The command procedure and options are the same for both swept solids and surfaces. Sweeping an open shape creates a surface. See Figure 7-1. The objects that can be swept to create surfaces include lines, arcs, elliptical arcs, 2D polylines, 2D or 3D splines, and 3D edge subobjects. Sweeping a closed shape creates a solid by default, but surfaces may be created as well. See Figure 7-2. Closed shapes that can be swept include circles, ellipses, closed 2D polylines, closed 2D splines, regions, and 3D solid face subobjects. The sweep path can be a line, arc, circle, ellipse, elliptical arc, 2D or 3D polyline, 2D or 3D spline, helix, or 3D edge subobject. SWEEP Ribbon Home Modeling Solid Solid Surface Create Sweep Type SWEEP Sweeps and Lofts CHAPTER 7 7