AutoCAD and Its Applications—Comprehensive 2020, 27th Edition Page 298 (1370 of 1650)

Copyright Goodheart-Willcox Co., Inc. 298 AutoCAD and Its Applications—Advanced 7. Move the top edge of the left-hand face on the 20″ extrusion created in step 6 down 4″. 8. Move each vertical edge of the 20″ extrusion 6″ toward the center of the duct. 9. Mirror a copy of the 20″ extrusion to the opposite side of the tee junction. The completed drawing should look like Figure 11-35. NOTE NOTE For many of the previously discussed subobject editing techniques, you may fi nd it diffi cult to edit an object after a complex composite solid is created, especially if it has multiple fi llets. You may fi nd it necessary to select the subobject, delete it, and start the process over. Or, you may fi nd it necessary to add geometry to the existing solid using the UNION command and then edit the new object as needed. Figure 11-34. The face of the revolved elbow is extruded 72″. The face of the right branch is extruded 108″. The right duct is then extruded 26″ and the left face of that extrusion is extruded 20″. Figure 11-35. The reducer is mirrored to create the final assembly.

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Copyright Goodheart-Willcox Co., Inc. 298 AutoCAD and Its Applications—Advanced 7. Move the top edge of the left-hand face on the 20″ extrusion created in step 6 down 4″. 8. Move each vertical edge of the 20″ extrusion 6″ toward the center of the duct. 9. Mirror a copy of the 20″ extrusion to the opposite side of the tee junction. The completed drawing should look like Figure 11-35. NOTE NOTE For many of the previously discussed subobject editing techniques, you may fi nd it diffi cult to edit an object after a complex composite solid is created, especially if it has multiple fi llets. You may fi nd it necessary to select the subobject, delete it, and start the process over. Or, you may fi nd it necessary to add geometry to the existing solid using the UNION command and then edit the new object as needed. Figure 11-34. The face of the revolved elbow is extruded 72″. The face of the right branch is extruded 108″. The right duct is then extruded 26″ and the left face of that extrusion is extruded 20″. Figure 11-35. The reducer is mirrored to create the final assembly.

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Copyright Goodheart-Willcox Co., Inc. Chapter 11 Subobject Editing 299 Other Solid Editing Tools Other Solid Editing Tools There are other tools that can be used in solid model editing. As you will learn in Chapter 12, the SOLIDEDIT command can be used to edit faces, edges, and vertices, much like subobject editing. In addition, you can extrude open or closed geometry with the PRESSPULL command, offset edges with the OFFSETEDGE command, and explode a solid with the EXPLODE command. These methods are discussed in the next sections. Presspull The PRESSPULL command allows you to create extrusions from open or closed 2D profi les, 3D curves, and 3D solid faces. You can extrude open 2D objects such as lines, polylines, splines, or arcs. You can also extrude objects forming closed areas such as circles, closed polylines, and regions. In addition, you can use the PRESSPULL command to add to or subtract from an existing solid by selecting and dragging a closed and bounded area of the solid. The extrusion is always applied perpendicular to the plane of the boundary, but can be in the positive or negative direction. When applied to the face of a solid, the PRESSPULL command is very similar to the Extrude Faces option of the SOLIDEDIT command, though dynamic feedback is provided for the extrusion with PRESSPULL. Once the command is initiated, you are prompted to select an object or bounded area to extrude. If you are selecting a closed boundary, pick inside the boundary. Then, drag the boundary to a new location and pick, or, if dynamic input is on, enter the extrusion distance. The PRESSPULL command stays active so repetitive selections can occur in a single command sequence. An example of using the PRESSPULL command to add material to or subtract material from a 3D model is shown in Figure 11-36. By extruding the cylinder in a positive direction, the new cylinder is automatically unioned to the existing part, Figure 11-36B. By extruding the cylinder in a negative direction, the cylinder is subtracted from the wedge, Figure 11-36C. Using the PRESSPULL command to create extrusions from open 2D objects is shown in Figure 11-37. As is the case when using the EXTRUDE command, the resulting object is a surface. When extruding a 3D face with the PRESSPULL command, the extrusion is applied perpendicular to the surface and the shape of adjacent faces is maintained. If the adjacent faces are at an angle to the selected surface, you can maintain the shape of the faces by pressing the [Ctrl] key. You can use this method to maintain the orientation of adjoining surfaces or to create a taper angle. Figure 11-38A shows a run of ductwork along the top of walls that are at an angle to each other. The ducts follow the wall angles. A redesign requires the angled ductwork to be expanded. In Figure 11-38B, the long duct along the angled wall has been expanded using the PRESSPULL command. Then, the adjacent face is selected with the [Ctrl] key to maintain the angle with the face of the long duct. In addition, the face of the next duct at the 90° wall corner is selected and extruded. The result is shown in Figure 11-38C. In Figure 11-38D, the four front wall ducts have been expanded and unioned to complete the design. NOTE NOTE The PRESSPULL command allows for multiple object selection. To select more than one object, use the Multiple option, hold down the [Shift] key, or right-click and select Multiple from the context-sensitive shortcut menu. PRESSPULL Ribbon Home Modeling Solid Solid Presspull Type PRESSPULL

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Copyright Goodheart-Willcox Co., Inc. Chapter 11 Subobject Editing 297 7. Use the REVOLVE command to turn the left-hand face of the 60″ extension into a new solid that is a 90° bend. Your drawing should now look like Figure 11-33. Editing Edges and Vertices 1. The bottom surface of the 28″ reducer must be level with the bottom of the tee junction and main trunk. Select the bottom edge of the reducer’s front face and move it down 4 15/16″. 2. Select the two top vertices on the 28″ reducer’s front face. Move the vertices down (negative Z) 3″. 3. Select the front, rectangular face of the 90° bend and extrude it 72″ into a new solid. 4. Select the front face of the 28″ reducer and extrude it 108″ into a new solid. 5. Select the front face of the new solid created in step 4 and extrude it 26″ to create a new solid that will be a tee junction. 6. Extrude the left-hand face of the tee junction 20″. See Figure 11-34. Figure 11-32. Two reducers are created by extruding faces from the tee junction. Figure 11-33. The left end of the 60″ extrusion is revolved 90° to create an elbow.

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