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738 Part IV ✦ Drawing in Three Dimensions Box Figure 23-13 shows a surface mesh box from the SE isometric viewpoint in the 3D Hidden visual style and a white background. Figure 23-13: A box from an isometric viewpoint commanding the 3D Hidden visual style. Here’s how to draw a box: 1. Enter 3d on the command line. Choose the Box option. 2. At the Specify corner point of box: prompt, specify the lower-left corner of the base of the box. 3. At the Specify length of box: prompt, specify the length of the box along the X axis. You can pick a point or enter a value. 4. At the Specify width of box or [Cube]: prompt, specify the width of the box along the Y axis. You can pick a point or enter a value. If you choose the Cube option, AutoCAD creates a cube with a width and height the same as the length that you just specified, and you don’t see the height prompt. 5. At the Specify height of box: prompt, specify the height of the box along the Z axis. Pick a point or enter a value. 6. At the Specify rotation angle of box about the Z axis or [Reference]: prompt, specify an angle. AutoCAD rotates the box in the XY plane. Press Enter if you do not want to rotate the box. You can also use the Reference suboption, which works like the Reference option of the ROTATE command. As you define the box, AutoCAD draws a temporary image in yellow to show you the result of your specifications. 32_788864 ch23.qxp 5/22/06 7:29 PM Page 738 739 Chapter 23 ✦ Creating 3D Surfaces Wedge Figure 23-14 shows a wedge. The prompts are the same as for the box, except that there is no Cube option. A wedge is half of a box. Figure 23-14: A wedge from an isometric viewpoint in the 3D Hidden visual style Here’s how to draw a wedge: 1. Enter 3d on the command line. Choose the Wedge option. 2. At the Specify corner point of wedge: prompt, specify the lower-left corner of the base of the wedge. 3. At the Specify length of wedge: prompt, specify the length of the wedge along the X axis. 4. At the Specify width of wedge: prompt, specify the width of the wedge along the Y axis. 5. At the Specify height of wedge: prompt, specify the height of the wedge along the Z axis. 6. At the Specify rotation angle of wedge about the Z axis: prompt, specify an angle. AutoCAD rotates the wedge in the XY plane. Press Enter if you don’t want to rotate the wedge. Pyramid You can draw pyramids with three- and four-sided bases. A pyramid with a three-sided base creates a four-sided object called a tetrahedron. You can top the pyramid with a point, a flat top or, for four-sided bases, a ridge. Figure 23-15 shows the various types of pyramids that you can draw. 32_788864 ch23.qxp 5/22/06 7:29 PM Page 739 740 Part IV ✦ Drawing in Three Dimensions Figure 23-15: You can draw all of these pyramidal shapes. Here’s how to draw the pyramids: 1. Enter 3d on the command line. Choose the Pyramid option. 2. At the Specify first corner point for base of pyramid: prompt, specify the first point (any point) on the base. 3. At the Specify second corner point for base of pyramid: prompt, specify the sec- ond point on the base. 4. At the Specify third corner point for base of pyramid: prompt, specify the third point on the base. 5. At the Specify fourth corner point for base of pyramid or [Tetrahedron]: prompt, specify the fourth point on the base or choose the Tetrahedron option (creates a pyramid with a base of three points). • If you chose the Tetrahedron option, at the Specify apex point of tetrahedron or [Top]: prompt, specify the apex (top point) or choose the Top option. AutoCAD prompts you for three top points. • If you specified a fourth base point, at the Specify apex point of pyramid or [Ridge/Top]: prompt, specify the apex (top point) or choose the Ridge or Top options. If you choose the Ridge option, specify the two points for the ridge. If you choose the Top option, specify the four top points. Specifying the apex or ridge can be tricky unless you know the absolute coordinates that you want. You can’t change viewpoints during the command. However, you can easily change the points later using grips. Another trick is to start any drawing command, such as LINE, before starting the pyramid. At the Specify first point: prompt, pick the point that you want to use for the first base point of the pyramid. Then press Esc to cancel the command. This leaves that point as the last point specified. Now define the base of the pyramid, using the same point as the first base point. When you need to specify the apex or ridge, you can use relative coordinates from the first base point. For example, to create an apex two units directly over the first base point, specify @0,0,2 for the apex. 32_788864 ch23.qxp 5/22/06 7:29 PM Page 740 741 Chapter 23 ✦ Creating 3D Surfaces When you use the Top option, AutoCAD provides a rubber-band line from each of the base corners in turn, letting you use relative coordinates from the base corners. You can also cre- ate a temporary 2D object before starting the pyramid to frame a ridge or top. Cone You can create full or partial cones. Figure 23-16 shows both types, as displayed in the 3D Wireframe visual style. Figure 23-16: You can draw full or partial cones. Follow these steps to create cones: 1. Enter 3d on the command line. Choose the Cone option. 2. At the Specify center point for base of cone: prompt, pick the center for the circle that makes the base of the cone. 3. At the Specify radius for base of cone or [Diameter]: prompt, specify the radius for the circle at the base or choose the Diameter option to specify the diameter. 4. At the Specify radius for top of cone or [Diameter] <0>: prompt, specify the radius of the top or choose the Diameter option and specify the diameter. If you accept the default of zero, you get a complete cone. If you specify a radius or diameter, you get a truncated cone. You can specify the base’s size to be larger than the top’s size. 5. At the Specify height of cone: prompt, specify the height. 6. At the Enter number of segments for surface of cone <16>: prompt, specify the number of mesh segments. A higher number results in a smoother-looking cone. Note 32_788864 ch23.qxp 5/22/06 7:29 PM Page 741 742 Part IV ✦ Drawing in Three Dimensions Sphere Drawing a sphere is quite easy. You just specify the center and radius, and then the number of segments to display in each direction. Figure 23-17 shows a sphere in the 3D Wireframe visual style. Figure 23-17: A sphere. Here’s how to draw a sphere: 1. Enter 3d on the command line. Choose the Sphere option. 2. At the Specify center point of sphere: prompt, specify a point. 3. At the Specify radius of sphere or [Diameter]: prompt, specify the radius, or choose the Diameter option to specify the diameter. 4. At the Enter number of longitudinal segments for surface of sphere <16>: prompt, type the number of north-south lines that you want. A higher number results in a smoother-looking sphere. 5. At the Enter number of latitudinal segments for surface of sphere <16>: prompt, type the number of east-west lines that you want. A higher number results in a smoother-looking sphere. The only tricky point with spheres is remembering that the center point is the center in all three dimensions. If you want to draw a ball on a table, it’s easy to specify the center on the plane of the tabletop —but you end up with a ball that’s half beneath the table. So plan ahead. Dome A dome is the top half of a sphere, as shown in Figure 23-18. The prompts are very similar to those for a sphere. Figure 23-18: A dome. 32_788864 ch23.qxp 5/22/06 7:29 PM Page 742 743 Chapter 23 ✦ Creating 3D Surfaces Follow these steps to draw a dome: 1. Enter 3d on the command line. Choose the Dome option. 2. At the Specify center point of dome: prompt, specify the center point of the circle that makes up the base of the dome. 3. At the Specify radius of dome or [Diameter]: prompt, specify the radius or use the Diameter option to specify the diameter. 4. At the Enter number of longitudinal segments for surface of dome <16>: prompt, type the number of north-south lines that you want. A higher number results in a smoother-looking dome. 5. At the Enter number of latitudinal segments for surface of dome <8>: prompt, type the number of east-west lines that you want. A higher number results in a smoother-looking dome. Notice that the default is 8 instead of 16 for the sphere because you’re drawing only half of a sphere. Dish A dish is the bottom half of a sphere, as shown in Figure 23-19. Actually, a bowl would be a better name for it. Figure 23-19: A dish. Follow these steps to draw a dish: 1. Enter 3d on the command line. Choose the Dish option. 2. At the Specify center point of dish: prompt, specify the center point of the circle that makes up the base of the dish. 3. At the Specify radius of dish or [Diameter]: prompt, specify the radius or use the Diameter option to specify the diameter. 4. At the Enter number of longitudinal segments for surface of dish <16>: prompt, type the number of north-south lines that you want. A higher number results in a smoother-looking dish. 5. At the Enter number of latitudinal segments for surface of dome <8>: prompt, type the number of east-west lines that you want. A higher number results in a smoother-looking dish. As with the dish, the default is 8 because you’re drawing only half of a sphere. As with spheres, remember that the center point is the center of the top of the dish, not its base. 32_788864 ch23.qxp 5/22/06 7:29 PM Page 743 744 Part IV ✦ Drawing in Three Dimensions Torus A torus is a 3D donut, as shown in Figure 23-20. Figure 23-20: A torus. Follow these steps to create a torus: 1. Enter 3d on the command line. Choose the Torus option. 2. At the Specify center point of torus: prompt, specify the center of the torus. 3. At the Specify radius of torus or [Diameter]: prompt, specify the radius of the torus, as shown in Figure 23-20, or use the Diameter option to define the diameter. 4. At the Specify radius of tube or [Diameter]: prompt, specify the radius of the tube or use the Diameter option to define the diameter. 5. At the Enter number of segments around tube circumference <16>: prompt, spec- ify the number of segments around the tube. 6. At the Enter number of segments around torus circumference <16>: prompt, spec- ify the number of segments around the torus. As with a sphere, a torus is half above and half below the center point in the Z direction. Mesh The 3D command has a Mesh option that creates a 3D Mesh. All you have to do is pick the four corners and the M and N mesh sizes. This is similar to a planar surface, except that you can choose the number of mesh lines during the command. Specify the four corner points in clockwise or counterclockwise order. Then specify the M and N mesh sizes. Figure 23-21 shows a mesh with M=8 and N=4. Segments around torus circumference Radius of tube Segments around tube circumference Radius of torus 32_788864 ch23.qxp 5/22/06 7:29 PM Page 744 745 Chapter 23 ✦ Creating 3D Surfaces Figure 23-21: A mesh with M=8 and N=4. The drawing used in the following exercise on drawing 3D polygon meshes, ab23-c.dwg, is in the Drawings folder on the CD-ROM. STEPS: Drawing 3D Polygon Meshes 1. Open ab23-c.dwg from the CD-ROM. 2. Save it as ab23-03.dwg in your AutoCAD Bible folder. The drawing is in architectural units. OSNAP should be on. Set running object snaps for endpoint and midpoint. 3. Enter 3d and choose the Box option. Follow the prompts to make the tabletop: Specify corner point of box: 1,1,30 ↵ Specify length of box: 4' ↵ Specify width of box or [Cube]: 3' ↵ Specify height of box: 1 ↵ Specify rotation angle of box about the Z axis or [Reference]: ↵ 4. Do a Zoom Extents to see the entire box. 5. Start the 3D command with the Box option again. Follow the prompts to make a leg: Specify corner point of box: 1,1 ↵ Specify length of box: 1 ↵ Specify width of box or [Cube]: 1 ↵ Specify height of box: 30 ↵ Specify rotation angle of box about the Z axis or [Reference]: 0 ↵ 6. Mirror the leg, from one side of the table to the opposite side, using midpoint object snaps for the mirror line. Then mirror the two legs in the other direction, so that you have four legs. Zoom out and pan as necessary to center the table in the drawing area. If you have trouble finding the midpoint object snaps, change the visual style to 2D Wireframe. Note On the CD-ROM 32_788864 ch23.qxp 5/22/06 7:29 PM Page 745 746 Part IV ✦ Drawing in Three Dimensions 7. Start the 3D command with the Dish option. Follow the prompts to create a bowl on the table: Specify center point of dish: 2',2',35-1/2 ↵ Specify radius of dish or [Diameter]: d ↵ Specify diameter of dish: 9 ↵ Enter number of longitudinal segments for surface of dish <16>: ↵ Enter number of latitudinal segments for surface of dish <8>: ↵ The dish’s diameter is 9, so its height is half that, or 4 1 ⁄2. The center of the dish is at height 35 1 ⁄2 because the tabletop is at 31 (31 + 4 1 ⁄2 = 35 1 ⁄2). 8. Type elev ↵. Change the elevation to 31. Leave the thickness at 0 (zero). 9. Start the 3D command with the Cone option. Follow the prompts to create a salt shaker: Specify center point for base of cone: 2',1'6 ↵ Specify radius for base of cone or [Diameter]: 1 ↵ Specify radius for top of cone or [Diameter] <0>: .5 ↵ Specify height of cone: 4 ↵ Enter number of segments for surface of cone <16>: 8 ↵ 10. Start the 3D command with the Sphere option. Follow the prompts to draw an orange in the bowl: Specify center point of sphere: 2',2',32-1/2 ↵ Specify radius of sphere or [Diameter]: d ↵ Specify diameter of sphere: 3 ↵ Enter number of longitudinal segments for surface of sphere <16>: 8 ↵ Enter number of latitudinal segments for surface of sphere <16>: 8 ↵ 11. Start the 3D command with the Cone option again. Follow the prompts to make a plate. (It may not seem logical to use a cone to make a flat plate. However, it works because you can create a truncated cone that is upside down and very shallow. It’s an unusual but interesting use for the CONE command.) Specify center point for base of cone: 1',1' ↵ Specify radius for base of cone or [Diameter]: 2 ↵ Specify radius for top of cone or [Diameter] <0>: 5 ↵ Specify height of cone: 1/2 ↵ Enter number of segments for surface of cone <16>: ↵ 12. Start the 3D command with the Wedge option. Follow the prompts to make a wedge of cheese on the plate: Specify corner point of wedge: 10,10 ↵ Specify length of wedge: 5 ↵ Specify width of wedge: 2 ↵ Specify height of wedge: 2 ↵ Specify rotation angle of wedge about the Z axis: 30 ↵ 13. Start the 3D command with the Pyramid option. Follow the prompts to draw a pyrami- dal pepper shaker: 32_788864 ch23.qxp 5/22/06 7:29 PM Page 746 747 Chapter 23 ✦ Creating 3D Surfaces Specify first corner point for base of pyramid: 2'6,2'6 ↵ Specify second corner point for base of pyramid: 1,0 ↵ Specify third corner point for base of pyramid: 0,1 ↵ Specify fourth corner point for base of pyramid or [Tetrahedron]: -1,0 ↵ Specify apex point of pyramid or [Ridge/Top]: t ↵ Specify first corner point for top of pyramid: 1/4,1/4,3 ↵ Specify second corner point for top of pyramid: -1/4,1/4,3 ↵ Specify third corner point for top of pyramid: -1/4,-1/4,3 ↵ Specify fourth corner point for top of pyramid: 1/4,-1/4,3 ↵ 14. Choose View➪ Visual Styles ➪ Conceptual. You can now visualize the drawing better. 15. Save your drawing. It should look like Figure 23-22. If you look carefully, you’ll see that the edge of the cheese wedge goes slightly through the plate. Figure 23-22: The table with a plate, wedge of cheese, bowl, orange, and nonmatching salt and pepper shakers. Drawing Revolved Surfaces A common way to define a surface is to revolve an outline around an axis. You can create some very complex surfaces in this way. AutoCAD offers two ways to create surfaces from the revolution of an outline. Understanding the REVSURF command The REVSURF command takes an object that defines an outline or profile— AutoCAD also calls it a path curve —and revolves it around an axis, creating a 3D polygon mesh. Figure 23-23 shows two examples of revolved surfaces. 32_788864 ch23.qxp 5/22/06 7:29 PM Page 747 [...]... your AutoCAD Bible folder You see a spline, as shown in Figure 2 3-3 5 In this exercise, you use the spline to draw some drapes 1 2 Figure 2 3-3 5: A spline 75 7 32 _78 8864 ch23.qxp 75 8 5/22/06 7: 29 PM Page 75 8 Part IV ✦ Drawing in Three Dimensions 3 Mirror the spline For the mirror line, turn on ORTHO and use 1 and 2 as shown in Figure 2 3-3 5 Don’t delete the original spline 4 Start the COPY command and select... the POLYGON command (For more information on the POLYGON command, see “Drawing Polygons” in Chapter 6.) A pyramid can come to a point, or you can truncate it You can also tilt the pyramid Figure 2 4-8 shows three variations on the pyramid 33 _78 8864 ch24.qxp 5/22/06 7: 41 PM Page 77 3 Chapter 24 ✦ Creating Solids and Editing in 3D New Feature The PYRAMID command is new for AutoCAD 20 07 Although there has... REVSURF command The prompts of the two commands ask for the same information but in a slightly different way Figure 2 3-2 7 shows two examples of the REVOLVE command, one that creates a surface and the other that creates a solid The arc is revolved around the line in each case, but when the line and the arc create a closed figure, the result is a solid 75 1 32 _78 8864 ch23.qxp 75 2 5/22/06 7: 29 PM Page 75 2 Part... toolbar (right-click any toolbar and choose Modeling) You can also access all of the solids commands by choosing Draw ➪ Modeling and then choosing the specific command from the submenu that opens Using editing commands in 3D Editing solids Determining solid properties ✦ ✦ ✦ ✦ 33 _78 8864 ch24.qxp 76 6 5/22/06 7: 41 PM Page 76 6 Part IV ✦ Drawing in Three Dimensions Figure 2 4-1 : You can create complex and realistic... command You can then use the dynamic UCS feature to temporarily change UCSs for each edge On the CD-ROM The drawing used in the following exercise on drawing edge surfaces, ab23-g.dwg, is in the Drawings folder on the CD-ROM STEPS: Drawing Edge Surfaces 1 Open ab23-g.dwg from the CD-ROM 2 Save it as ab2 3-0 7. dwg in your AutoCAD Bible folder You see four curves in a bounding box, as shown in Figure 2 3-3 9... curves ✦ Working with multiple types of 3D objects In the next chapter, you discover how to create true solids (well, true electronic ones, at least) as well as how to edit in 3D ✦ ✦ ✦ 76 3 32 _78 8864 ch23.qxp 5/22/06 7: 29 PM Page 76 4 33 _78 8864 ch24.qxp 5/22/06 7: 41 PM Page 76 5 24 C H A P T E R Creating Solids and Editing in 3D ✦ ✦ ✦ ✦ In This Chapter A lthough you can create great-looking models with surfaces,... 2 3-3 3 shows some ruled surfaces The pick points of the two objects affect the resulting curve If you pick them both on the same side, you get the type of curves shown in Figure 2 3-3 3 If you pick them on opposite sides, the curve intersects itself, as shown in Figure 2 3-3 4 Figure 2 3-3 3: Ruled surfaces 32 _78 8864 ch23.qxp 5/22/06 7: 29 PM Page 75 7 Chapter 23 ✦ Creating 3D Surfaces Figure 2 3-3 4: A self-intersecting... lines AutoCAD uses to display the model However, if the path curve is a polyline with straight segments, AutoCAD just displays one line at each segment vertex In Figure 2 3-2 4, SURFTAB1 is 6 and SURFTAB2 is 12 Figure 2 3-2 5 shows the same model with SURFTAB1 at 20 and SURFTAB2 at 5 to show the contrast between the two Figure 2 3-2 5: The same model re-created with SURFTAB1=20 and SURFTAB2=5 74 9 32 _78 8864... should look like Figure 2 3-3 0 Figure 2 3-3 0: The completed table 32 _78 8864 ch23.qxp 5/22/06 7: 29 PM Page 75 5 Chapter 23 ✦ Creating 3D Surfaces Working with the EXTRUDE command The EXTRUDE command creates a surface if you start with an open 2D figure, and a solid if you start with a closed 2D figure If you use the EXTRUDE command to create a surface, it is similar to the TABSURF command, but offers more... the CD-ROM STEPS: Drawing Revolved Surfaces 1 Open ab23-d.dwg from the CD-ROM 2 Save it as ab2 3-0 4.dwg in your AutoCAD Bible folder The path curve and axis are already drawn This drawing was saved using the Conceptual visual style 3 Choose Draw ➪ Modeling ➪ Meshes ➪ Revolved Mesh 4 At the Select object to revolve: prompt, select the polyline to the right 32 _78 8864 ch23.qxp 5/22/06 7: 29 PM Page 75 1 Chapter . ab23-d.dwg, is in the Drawings folder on the CD-ROM. STEPS: Drawing Revolved Surfaces 1. Open ab23-d.dwg from the CD-ROM. 2. Save it as ab2 3-0 4.dwg in your AutoCAD Bible folder. The path curve and. when the line and the arc create a closed figure, the result is a solid. New Feature 32 _78 8864 ch23.qxp 5/22/06 7: 29 PM Page 75 1 75 2 Part IV ✦ Drawing in Three Dimensions Figure 2 3-2 7: When the. the circle and going down to the floor. End the LINE command. On the CD-ROM Caution 32 _78 8864 ch23.qxp 5/22/06 7: 29 PM Page 75 3 75 4 Part IV ✦ Drawing in Three Dimensions Figure 2 3-2 9: The tabletop. 5.
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