271 Copyright Goodheart-Willcox Co., Inc. Learning Objectives After completing this chapter, you will be able to: Select subobjects (faces, edges, and vertices). Edit solids using grips. Edit fi llet and chamfer subobjects. Edit composite solid model subobjects. Edit face subobjects. Edit edge subobjects. Edit vertex subobjects. Extrude a 2D or 3D object using the PRESSPULL command. Offset planar face edges using the OFFSETEDGE command. Grip Editing Grip Editing There are three basic types of 3D solids in AutoCAD. The commands BOX, WEDGE, PYRAMID, CYLINDER, CONE, SPHERE, TORUS, and POLYSOLID create 3D solid primitives. Swept objects are 3D solids created from closed profi les using the EXTRUDE, REVOLVE, SWEEP, and LOFT commands. Finally, 3D solid composites are created by a Boolean operation (UNION, SUBTRACT, or INTERSECT) or by using the SOLIDEDIT command. The SOLIDEDIT command is discussed in Chapter 12. Smooth-edged solid primitives are achieved by converting mesh objects to solids. There are two basic types of grips—base and parameter—that may be associated with a solid object. These grips provide an intuitive means of modifying solids. Base grips are square and parameter grips are typically arrows. The editing techniques that can be performed with these grips are discussed in the next sections. 3D Solid Primitives The 3D solid primitives all have basically the same types of grips (base and param- eter). However, not all grips are available on all primitives. All primitives have a base grip at the centroid of the base. This grip functions like a standard grip in 2D work. It can be used to stretch, move, rotate, scale, or mirror the solid. Subobject Editing CHAPTER 11 11
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