autocad 2008 autocad lt 2008 no experience required - phần 10 docx

Building the Balcony You’re nearly done building the cabin. The next step is to make the balcony using Booleans and the Slice tool. 1. Make a new layer called 3D-Balcony, assign it color 24, make it cur- rent, and then thaw the Balcony layer and freeze the other 3D layers. 2. Choose the Cylinder primitive tool on the 3D Make control panel to create a cylinder solid to represent the space enclosed by the balcony wall. Use the Center osnap to locate the center point of the arcs that represent the balcony wall. Select a radius of 4'-6" and a height of 5'-0". 3. Move this cylinder up 10". 4. Draw a second cylinder using the same center point, with a radius of 5' and a height of 4'. Be sure to pick the center of the 2D balcony arcs, not the center of the 3D cylinder. 5. Start the Subtract command, and subtract the smaller cylinder from the larger cylinder to form a bowl shape (see Figure 16.21). FIGURE 16.21: The beginning of the balcony Modeling in 3D 633 26531ch16.qxd 3/30/07 10:13 PM Page 633 6. Expand the 3D Make control panel on the Dashboard by clicking the double arrows that appear when you place your cursor over the darker gray area to the left of the tools. The panel expands downward and makes several new tools accessible. Click the Slice button; then, back in the drawing, select the new balcony, and press ↵. 7. At the first prompt, enter yz↵. This defines the plane that you’ll use to slice the balcony. 8. At the second prompt, pick the bottom corner of the cabin wall, where the bottom of the balcony meets the corner. Doing so positions the YZ cutting plane in line with the exterior wall surface against which the balcony wall butts. 9. At the third prompt, click a blank spot below and to the right of the balcony. This tells AutoCAD the side of the cutting plane where the desired objects are located. The shape is cut in half, the inside half is deleted, and the balcony is complete (see Figure 16.22). FIGURE 16.22: The balcony after using the slice tool Putting a Roof on the Cabin You’ll finish the 3D model of the cabin by constructing a roof. The edge of the roof will be a different color from the roof surface, so you’ll make them as two separate objects, each on its own layer. The edge will be a solid, and the sloping part will be a set of surfaces. Follow these steps: 1. Create two new layers: 3D-Roof-Edge with color 32 and 3D-Roof with color 114. Make 3D-Roof-Edge current. 2. Freeze all 3D layers except the two new ones, and freeze all the 2D layers except Roof. Only the roof is visible. Chapter 16 • Creating 3D Geometry634 26531ch16.qxd 3/30/07 10:13 PM Page 634 3. Use the Box command on the 3D Make control panel to make a box that is 6" high and sits on the four corners of the roof. 4. Move the box up 9'. Then, copy the ridgeline and hiplines of the roof up to the top edge of the box. 5. Select the objects, and use the Layer Control drop-down list to change these copied lines to the 3D-Roof_Edge layer. Then, turn off the Roof layer (see Figure 16.23). FIGURE 16.23: The solid box is made, and the copied rooflines are moved to the 3D-Roof_Edge layer 6. Start the Stretch command (on the Modify toolbar), and use a cross- ing window to select just the ridgeline and the ends of the four hip lines that touch the ridgeline. 7. Press ↵. Click a blank part of the drawing area for the base point, and then enter @0,0,3'↵. The roof is stretched up 3' (see the left of Figure 16.24). 8. Make the 3D-Roof layer current, and then choose Draw ➣ Modeling ➣ Meshes ➣ 3D Face. 9. With the Endpoint osnap, start at the leftmost corner of the sloping planes, and pick the four corners of the front plane of the roof. Then, at the Specify third point or [Invisible] <exit>: prompt, move Modeling in 3D 635 26531ch16.qxd 3/30/07 10:13 PM Page 635 to the rightmost corner, and click this point twice. Follow the diagram on the right of Figure 16.24. Press ↵ to end the 3D Face command. FIGURE 16.24: The ridge and hip lines are stretched up (left) and the sequence of picks for the first two 3D faces (right) 10. Repeat steps 8 and 9 for the back and left surfaces of the roof. 11. Turn off the 3D-Roof layer, and erase the ridgelines and hiplines. Turn the layer back on, and thaw the remaining 3D layers. Your drawing should look like Figure 16.25. 5–Pick twice 1 4 3 2 Chapter 16 • Creating 3D Geometry636 26531ch16.qxd 3/30/07 10:13 PM Page 636 FIGURE 16.25: The completed cabin in the Conceptual visual style 12. Save this file as Cabin16c.dwg. Using the Orbit Tools Now that you’ve had a chance to set and reset various 3D views, check out the three orbit tools that are on the 3D Navigation control panel: Constrained Orbit, Free Orbit, and Continuous Orbit. You can find them on the fly-out menu that by default displays the Constrained Orbit icon. Follow these steps: 1. Make 3D-Walls-Ext current; then, freeze the 3D-Roof and 3D- Roof_Edge layers. 2. With the Visual Style set to Conceptual and the 3D View set to South- east Isometric, click and hold the Constrained Orbit icon on the 3D Navigation control panel to open the toolbar fly-out menu; then move down to the fly-out toolbar, select the Constrained Orbit icon, and move the cursor onto the drawing area. It changes into an atom- like symbol. 3. Click and drag the cursor around in the drawing area, and note how the 3D model rotates as you move the cursor. This tool is called con- strained because if you move the view to one of the cabin from directly overhead or directly underneath, you can’t keep moving the cabin in a fashion that causes it to tumble over and over. Modeling in 3D 637 26531ch16.qxd 3/30/07 10:13 PM Page 637 4. Try the other two orbiting options. Click and hold the Constrained Orbit icon to open the toolbar fly-out. Then, move the cursor down, and release the mouse button when the cursor is on one of the other two icons. Here’s how they work: Ǡ Free Orbit superimposes a green circle called an arcball over the 3D model. Smaller circles appear at the quadrant points of the larger circle. How the model moves depends on whether you click and drag inside or outside the big circle or within one of the small circles (see Figure 16.26). FIGURE 16.26: Changing the view with the Free Orbit tool Ǡ Continuous Orbit creates an animation of the model spinning. Click and drag the cursor in a straight direction; then, release the mouse button as you’re dragging. This begins the spin. The direc- tion of your drag determines the direction of spin; and, to a degree, the speed of your drag determines how fast the model spins. 5. When you’re finished, thaw the 3D-Roof and 3D-Roof_Edge layers, and reset the view to Southeast Isometric. Chapter 16 • Creating 3D Geometry638 26531ch16.qxd 3/30/07 10:13 PM Page 638 Getting Further Directions in 3D Covering 3D in real depth is beyond the scope of this book, but I can mention a few other tools and features that you might enjoy investigating. First, I’ll sum- marize a few of the solids and surface-modeling tools that I didn’t cover in the tutorial on the cabin. Then, we’ll take a quick look at the rendering process as it’s approached in AutoCAD. Using Other Solids Modeling Tools You used the Box and Cylinder primitive solid tools to build up the model of the cabin. There are several other primitive shapes, all found on the top row of the 3D Navigation control panel. Four of them are shown and described here. Sphere You specify the center point and radius or diameter. Cone You specify the center point of the base, the radius of the base, and the height of the pointed tip. The base is parallel to the XY plane, and the height is perpendicular to it. Wedge The wedge has a rectangular base and a lid that slopes up from one edge of the base. You specify the base as you do in the Box tool and then enter the height. Torus This is a donut shape. You specify a center point for the hole, the radius of the circular path that the donut makes, and the radius of the tube that follows the circular path around the center point. In the second row of the Make control panel are tools for creating solids by mov- ing 2D shapes in the third dimension: Sphere Cone Wedge Torus Getting Further Directions in 3D 639 26531ch16.qxd 3/30/07 10:13 PM Page 639 Extrude Select a closed 2D shape such as a rectangle or a circle. Then, specify a height for the extrusion or a path to extrude along. If the extrusion is straight up, you enter an angle to taper the edges away from the vertical. Revolve Select a closed 2D shape, and then define the axis and the angle of rotation. There are many tools for modifying solids. When you formed the cabin walls, floor, and balcony, you used Union and Subtract, as well as Slice. Another solids- editing tool, Intersect, finds the volume that two solids have in common when they partially occupy the same space. Its icon is in the third row of the 3D Navi- gation control panel, with Union and Subtract. You select solids that are collid- ing, and AutoCAD creates a solid from their intersection. Intersecting solids The intersection Shape and axis Shape rotated 180º Vertical extrusion Object to extrude Tapered vertical extrusion Extrusion along a curved path Chapter 16 • Creating 3D Geometry640 26531ch16.qxd 3/30/07 10:13 PM Page 640 These are only a few of the numerous tools for creating and modifying solids, but they should be enough to get you started. Using Surface-Modeling Tools Surface modeling has its own set of tools. Choose Draw ➣ Modeling ➣ Meshes to open the 3D Meshes menu. You’ve already used the 3D Face command. Here is a brief description of a few of the other tools on this menu: Revolved Mesh Creates a 3D surface mesh by rotating a 2D curved line around an axis of revolution. Tabulated Mesh Creates a 3D surface mesh by extruding a 2D object in a direc- tion determined by the endpoints of a line, an arc, or a polyline. Ruled Mesh Creates a 3D surface mesh between two selected shapes. Edge Mesh Creates a 3D surface mesh among four lines that are connected at their endpoints. Each line can be in 2D or 3D, and the original shape must be a boundary of a shape that doesn’t cross or conflict with itself. Edge mesh Ruled mesh Tabulated mesh Revolved mesh Getting Further Directions in 3D 641 26531ch16.qxd 3/30/07 10:13 PM Page 641 Most 3D models today utilize the solid-modeling tools for their basic shapes because the tools for adding, subtracting, slicing, and so forth, are easy to use and allow complex shapes to be fabricated quickly. Still, surface modeling has its uses, and sometimes a shape will lend itself to surface over solid modeling. Any serious 3D modeler will be familiar with both sets of tools. Are You Experienced? Now you can… 0 change visual styles 0 create linear 3D objects with the Polysolid tool 0 extrude 2D shapes into 3D geometry 0 cut holes in objects using the Subtract Boolean tool 0 resize 3D objects using grips 0 create 3D surface 0 navigate in a 3D scene Chapter 16 • Creating 3D Geometry642 26531ch16.qxd 3/30/07 10:13 PM Page 642 [...]... image-viewing software The larger file is much crisper than the smaller image at the expense of increased rendering time This has been a brief introduction into the world of 3D and rendering in AutoCAD, but you should now be oriented to the general way of doing things and have enough tools to experiment further For a more in-depth discussion of the process, including rendering, see Mastering AutoCAD 2008. .. the process, including rendering, see Mastering AutoCAD 2008 and AutoCAD LT 2008 (Wiley, 2007) by George Omura 6 6 3 26531ch17.qxd 3/30/07 6 6 4 10: 12 PM Page 664 Chapter 17 • Materials and Rendering Are You Experienced? Now you can… 0 create and manipulate cameras 0 add sunlight to a scene 0 place a point light 0 specify a scene’s real-world location 0 add materials to objects 0 render to a file 26531glos.qxd... 9 26531ch17.qxd 3/30/07 6 6 0 10: 12 PM Page 660 Chapter 17 • Materials and Rendering 11 Make the 3D-Glazing layer current, and then freeze all the other layers 12 Select all the glazing objects in the drawing With the glass material selected in the Materials palette, click the Apply Material to Objects button below the sample area 13 Thaw the 3D-Pivot-Doors and 3D-Win-Frame layers, make one of them... Camera Location grip approximately 25' in the Z direction to get higher view of the structure 6 4 7 26531ch17.qxd 3/30/07 6 4 8 10: 12 PM Page 648 Chapter 17 • Materials and Rendering 10 Expand the drop-down list in the 3D Navigate control panel, and notice that the two cameras now appear in the list Select Cam Southeast; your drawing area changes to view the scene from the selected camera, as shown in... Render control panel From the Select Render Preset drop-down list, select Presentation 26531ch17.qxd 3/30/07 10: 12 PM Page 663 Adding Materials 5 Open the Output Size drop-down list, and then choose Specify Output Size to open the Output Size dialog box 6 Set Width to 2000 and Height to 1600, and then click OK This is the resolution required to print a 10" × 8" image at 200 dots per inch (dpi) 7 Click... Light Source AutoCAD has three kinds of lighting: Point light All light rays are emitted from a single location and diverge as they get farther away An incandescent lightbulb is a real-world example of a point light, even though the light does not travel toward the light’s fixture 26531ch17.qxd 3/30/07 10: 12 PM Page 649 Creating a Lighting Scheme Distant light All light rays are parallel Although the... box (see Figure 17.6) 9 In the Region drop-down list below the map, select North America Below that, in the Nearest City drop-down list, select Bangor, ME A red cross appears over Bangor in the map Because you’ve already set the date and time, the Time Zone drop-down list displays the accurate time zone Click OK to close this dialog box If a particular city is not listed, you can uncheck the Nearest... material library that ships 26531ch17.qxd 3/30/07 10: 12 PM Page 657 Adding Materials with AutoCAD 2008 with the rest of the package You can assign materials to your drawing objects from several premade libraries, you can create materials from scratch, or you can edit materials that originate from the libraries In the next exercise, you will apply materials from AutoCAD s libraries 1 Choose Tools ➣ Palettes... to process this image When it is done, your Render dialog box should look similar to Figure 17.12 The background image not only appears behind the cabin and ground, but it also contributes light to the scene N O T E Rendering is a processor-intensive function It’s not uncommon to experience a lag in computer performance or to hear increased cooling fan activity F I G U R E 1 7 1 2 : The cabin rendered... I’m sure you noticed the small black squares being replaced one at a time by small areas of the rendered drawing This indicates that AutoCAD is using bucket rendering Before the rendering process begins, AutoCAD determines the sequence to process the squares, called buckets, in order to maximize the memory usage and thus increase the efficiency of the rendering 26531ch17.qxd 3/30/07 10: 12 PM Page . can find them on the fly-out menu that by default displays the Constrained Orbit icon. Follow these steps: 1. Make 3D-Walls-Ext current; then, freeze the 3D-Roof and 3D- Roof_Edge layers. 2. With. set of surfaces. Follow these steps: 1. Create two new layers: 3D-Roof-Edge with color 32 and 3D-Roof with color 114. Make 3D-Roof-Edge current. 2. Freeze all 3D layers except the two new ones,. Reproduce Views 647 26531ch17.qxd 3/30/07 10: 12 PM Page 647 10. Expand the drop-down list in the 3D Navigate control panel, and notice that the two cameras now appear in the list. Select Cam Southeast;