Hướng dẫn sử dụng Coreldraw x5 - part 58 doc

A lthough CorelDRAW is a 2D vector drawing application, the extrude feature adds objects to create an illusion of a third dimension, one of depth. Depending on the intricacy of the parent object—and how you pose the object and light it—extruded objects can open up a whole new world of design opportunities and extend your style of illustration to present your audience with scenes they can step right into! This chapter takes you through the rich feature set of the Extrude tool, offers some creative possibilities for its use, and gets your head around the initial challenges of navigating 3D space in CorelDRAW. Download and extract all the files from the Chapter19.zip archive to follow the tutorials in this chapter. How Extrude Works CorelDRAW’s extrude effect examines the geometry of an object, which can be a single or a compound path (two or more combined paths). Then, with your input, it creates extensions to all path segments, which are dynamic objects that are created to suggest that they recede into the distance to a vanishing point. (See Chapter 18 on perspective vanishing points.) Figure 19-1 is a rendered illustration of the 3D scene.cdr file, one of the several files you downloaded. By the end of this chapter, you’ll know how to un-extrude the compositions, how these extrudes are designed, and how to create similar work. One thing to remember: even the most complex object you extrude probably won’t convey a complete artistic idea— you need to use other CorelDRAW tools to complete a scene you’re happy with. For example, the train composition uses several extruded objects, the toaster uses a Contour effect to create the shadow beneath the objects, and the tabletop was first created by extruding shapes, but then all the shadows you see were manually drawn on top of areas that look stark without a supporting shadow object here and there. The Extrude tool can get you 75 percent of the way you want to go with design, but you need to be imaginative to place the extruded object in context, within a scene, to build a complete graphical idea. That’s what the rest of this book is for! When an extrude effect is applied to an object, the original becomes a control object, and the extrude effect objects become a dynamically linked group. Any editing you then perform on the properties of the control object, such as fills and edits to the outline of the control object, are immediately updated in the linked extrude group. The extrude group itself can also be modified in ways that increase the intricacy and photorealism of the effect; you can change the depth, color, lighting, and rotation of the extrude effect. Be aware that both lighting and the control object’s geometry have an impact on how many extrude group objects are created. Although you don’t usually need to concern yourself with how many objects are dynamically created to make an extrude, the sheer number of objects can slow down redraws of your page when you have, for example, hundreds of objects in the extrude group. When CorelDRAW creates an extrude group, it calculates lighting (when you use lighting, covered later in this chapter) and creates extrude 554 CorelDRAW X5 The Official Guide group objects based on curved path segments in the control object. Here you can see a star- shaped control object with lighting; the object has a Radial fountain fill, and it’s an interesting design in Enhanced view. At right, the page is viewed in Wireframe, and 48 objects are grouped in the extrude effect. CHAPTER 19: Extruding Objects 555 19 FIGURE 19-1 Imagine what an object looks like when projected into a third dimension, and then manually add what’s missing from your complete idea. Extrude on straight path shape, with lighting, Enhanced view Wireframe view, 48 extrude group objects Here, a much more complex control object is used for an extrude. It not only is a compound path, but also its path segments are curved. In Wireframe view it’s evident that the extrude group is composed of more objects than the star-shaped extrude. No lighting is used in the extrude effect, which in turn limits the number of extrude group objects CorelDRAW has to create, and it is a fairly interesting design. If lighting is now applied, you can see that the number of extrude control objects created to represent the curved paths with added lighting is an order of magnitude more. This isn’t a warning to fellow Corellians to limit the intricacy of extrude objects you design, but rather a point of information. If you own a video card with lots of RAM yet suddenly find you’re getting slow screen redraws, consider going to a less refined view such as Normal or Draft via the View menu. Also consider reading “Simplifying an Extrude” later in this chapter. CorelDRAW uses fountain fills for extrude objects on two occasions: ● When the control curve (the parent object) has a fountain fill and your Color setting for the extrude shapes is set to Object Fill. ● When you use the Color Shading setting for extrude objects. Either of these conditions not only can create a lot of extrude shapes, but each shape also has a more complex fill than Uniform color. As you learn to create elegant extrude objects, consider these two circumstances if you’re not printing the objects as seen on your monitor (you might not have enough printer memory), or if your screen redraws are slower than you expect (you’re commanding too many operations). 556 CorelDRAW X5 The Official Guide Wireframe view, 118 extrude group objects Extruded object with flat fill Extrude on curved path shape, with lighting, Enhanced view Wireframe view, 890 extrude group objects Choosing and Applying an Extrude Effect The extrude effect can be applied interactively using the Extrude tool, located in the toolbox with other effects tools, or you can choose from the Presets list to instantly create a 3D object. While you’re using this tool, the property bar provides all the extrude options for setting the properties of the effect. Browse the property bar options, as shown in Figure 19-2. Options are grouped into areas for saving your applied extrusions as Presets, controlling the shape, depth, vanishing point position, rotation, lighting, color, and bevel effects. CHAPTER 19: Extruding Objects 557 19 FIGURE 19-2 The property bar holds all the options for defining and saving the look of an extrude. Preset options Extrusion type Vanishing point coordinates Depth Vanishing point properties Extrude Rotation Page or object vanishing point Copy Extrude Properties Color Bevels Lighting Clear Extrude Reset Rotation Extrude tool This happens to almost all CorelDRAW users: you’ve made only one copy of an object you’ve extruded, and now that you’ve extruded and rotated it, you want to save a copy of the object in its original form—not extruded, and not distorted or rotated. Do not copy and paste the Control Curve; doing this does not return it to its original orientation on the page. Instead, make a copy of the entire extrude group, double-click the group using the Pick tool to display Extrude options on the property bar, click the Extrude Rotation button, click the Reset Rotation icon at bottom left, and then click the Clear Extrude button on the property bar. Your original shape now contains the same number of nodes, the same curve segments, and the same color. Navigating the Interactive Markers When you decide to manually extrude a shape, interactive markers appear around the resulting object after you perform the first step in an extrude: you click-drag the face of the object you want to be the control object. The interactive markers offer you control over the position, depth, and vanishing point position for the 3D object. You’ll be creating a 3D object by hand in the following tutorial, so it’s good to familiarize yourself now with the elements that surround a 3D extruded shape, as shown in Figure 19-3. 558 CorelDRAW X5 The Official Guide FIGURE 19-3 These control handles are used after an object is initially extruded, to change the appearance of the extrude. Extrude outline preview Extrude group Vanishing point marker Depth slider Extrude Tool cursor Original object Center marker Alternatively, you can apply a Preset extrude effect to receive a 3D version of a shape in lightning time; however, you might want hands-on control over the creation of an extrude effect. Follow this tutorial to get a handle on what some of the property bar options do to an extrude effect; in no time, you’ll be able to “sculpt” whatever you envision as a scene that has objects with depth. Getting Deep with the Extrude Tool 1. Create an object to be the control object for the extrude. A rectangle will produce results that make the relationship between the face of the object and the sides very clear, but not very artistic unless you’re into cubism. Try a star shape for more dramatic extrude results. Give the shape a fill (a fountain fill will produce a stunning effect), and give the outline a contrasting color such as white so you can visually track where the extrude objects are created. 2. Choose the Extrude tool, and your cursor changes to the Extrude Tool cursor, hard to mistake for the Pick or a pen tool. When held over your object, the cursor indicates a start extrude position by using a tiny shape with a direction line below the symbol of an extruded cube. 3. Drag from the center of your object outward in any direction, but don’t release the mouse button. The control object now has interactive markers and a wireframe preview of the front and back boundaries of the extrude, the front of the object is bound by a red outline, and the back of the 3D shape is bound by a blue outline. The preview indicates the length and direction of the extrude effect and the X symbol you’re dragging is the vanishing point. As discussed in Chapter 18, a vanishing point is a geometric indicator of where parallel lines on a surface would converge at the horizon if the surface actually were to extend into the horizon. 4. Drag the vanishing point X symbol around the page; not only does the preview outline change, but more importantly, the view on the 3D object also changes. When the vanishing point is above the control object, you’re looking down on the object; similarly, you move your view to expose the side of an object in direct correlation to the position of the vanishing point. 5. As you use the Extrude tool, you define both the direction of the 3D object and the depth. Try dragging the Depth slider toward and then away from the control object. Notice how you first make the extrude a shallow one, and then a deeper one, all the while the sides extend in the direction of the vanishing point. At any time from when you create the object by releasing the cursor, you can also set the object depth by using the depth spin box on the property bar. 6. Click outside of the object, and the extrude operation is complete. However, because extrude is a dynamic effect, you can change the appearance of the extrude at any time in the future by double-clicking either the extrude group or the control object with the Pick tool to once again display the interactive handles. CHAPTER 19: Extruding Objects 559 19 Using the Extrude Tool and Property Bar Like other effects, extrusions can be set using the property bar. Using the Extrude tool, you’ll see several cursor states depending on where the cursor is, which indicate what operation can be performed at any given point on the extrude group. Let’s take a look at the different cursors and what they indicate in the following sections. Interactive Extrude Tool States The Extrude Tool cursor, shown here, changes appearance based on what it’s over in your document. When the cursor is held over an object that can be extruded, the cursor features a start symbol. If an object cannot be extruded, the cursor features the international “No” (x) symbol. Most shapes you draw with the pen tools except artistic media can be extruded. If you have your heart set on extruding artistic media strokes, the strokes need to be first broken from the control path ( CTRL+K) and then grouped; bitmaps cannot be extruded at all (but the 3D effects on the Bitmaps menu can be used to make perspective and emboss effects). You can only extrude one object at a time: you’ll get the “No Can Do” cursor if you select more than one object and then try to use the tool. Grouped objects can be successfully extruded; however, you can no longer ungroup them—you need to clear the extrude before you can select and edit only one of the group. Objects you want to extrude don’t have to be filled. You can create interesting wireframes similar to those you’d see in a technical drawing by extruding objects that have an outline width but no fill. Setting Extrusion Shape The Extrusion Type selector, shown next, offers six different shape types with which you can control both the direction of the extrude and whether you need wide-angle, small perspective, or totally isometric (no perspective) 3D objects. Depending on the type you choose, your extrusion can extend toward the back or front relative to the control object. Choosing a front style causes the vanishing point to project from the front of your object; choosing a back style does the opposite. Because you’re working with geometric solids, 560 CorelDRAW X5 The Official Guide Normal state Start object Chosen object can’t be extruded (it needs to be simplified or it’s a bitmap). when you choose a back style, the direction of the extrude will looked mirrored, although in wireframe view it’s clear that the object inverted itself, its back side projecting forward instead of into the distance. Icons in the selector indicate each shape type, with the darkened outline indicating your original object. Here are examples of the six different perspectives, which were created in order from the selector; see how the selector icons fairly represent each style. ● Small Back This option (the default setting) causes the extrusion and vanishing point to be layered behind your original object. Small Back is perhaps the most commonly applied extrusion type. ● Small Front This causes the extrusion and vanishing point to be layered in front of your original object. ● Big Back This option causes the extrusion to be layered behind your original object, while the vanishing point is in front. ● Big Front This causes the extrusion to be layered in front of your original object, while the vanishing point is in back. CHAPTER 19: Extruding Objects 561 19 Small Back Small Front Big Back Big Front Front Parallel Back Parallel ● Front Parallel This causes the extrusion to be layered in front of your object so that the extruded surfaces appear parallel to the original surfaces. When this option is selected, the vanishing point sets the depth of the extrusion, while the actual depth option is unavailable. It’s interesting to note that if you light a Back Parallel and a Front Parallel extrude with the same light setup, the two extrude groups appear to be lit differently. ● Back Parallel This option causes the extrusion to be layered behind your original object so that the extruded surfaces appear parallel to the original surfaces. When this option is selected, the vanishing point sets the depth of the extrusion, while the actual depth option is unavailable. No true vanishing point is used in this style. Setting Extrude Depth Extrude Depth is based on the distance between the control object and the vanishing point. You will get different appearances using the same Depth value but different styles, and Extrude Depth can be set as high as 99. Figure 19-4 shows a shallow and a deep extrude, using two different Depth values but the same extrude style. You can control object depth manually by dragging the interactive depth slider on top of the object, or enter values in the num box on the property bar (press ENTER after typing a value; the spin box controls update the object without the need to press ENTER). 562 CorelDRAW X5 The Official Guide FIGURE 19-4 Go for the subtle—or the dramatic—by changing the Depth setting on the extrude effect control object. Depth set to 65 Depth set to 25 Depth sliders indicate relative depth. Setting Vanishing Point Properties The direction of the vanishing point determines only the point toward which objects diminish; it does not control whether the extruded portion extends from the front or back of the object. Vanishing points can be set on four of the six extrusion styles: Small Back, Big Back, Small Front, and Big Front. The sides of the extruded portions created in the Front Parallel or Back Parallel types never converge; these are isometric views, and therefore there is no horizon, so no vanishing point. Using the property bar options shown here, you can lock an extrusion’s vanishing point, copy vanishing points from an existing extrusion, and share vanishing points between extruded objects. Here are the options for vanishing points—how they can be set and shared between different extruded objects: ● Locking to the object Choosing the VP Locked To Object option (the default setting) fixes the vanishing point to a position relative to the object, regardless of where the original extruded object is positioned. ● Locking to the page VP Locked To Page offers the option to tack the vanishing point to your page, forcing the extrusion to diminish toward a fixed page position, no matter where the original object is moved. Try this out to see for yourself the worth of this setting: lock the vanishing point of an extruded object to the page, and then move the object; you’ll see that the sides of the extrude dynamically update to always show the correct perspective of the object. ● Copying VP from Copying a vanishing point by using the Copy VP From command lets you set up several extruded objects on a page; in a few clicks the objects all appear to be facing the same direction, at a common point of view from the audience’s perspective. Immediately after you choose Copy VP From, your cursor changes to a vanishing point targeting cursor (a really, really large arrow), which you use to target any other extruded object on your document page, with the CHAPTER 19: Extruding Objects 563 19 Vanishing Point Position Vanishing Point Properties Selector VP Object/VP Page (vanishing point relative page/object center) option . with the elements that surround a 3D extruded shape, as shown in Figure 1 9-3 . 558 CorelDRAW X5 The Official Guide FIGURE 1 9-3 These control handles are used after an object is initially extruded,. the extrude group. When CorelDRAW creates an extrude group, it calculates lighting (when you use lighting, covered later in this chapter) and creates extrude 554 CorelDRAW X5 The Official Guide group. the spin box controls update the object without the need to press ENTER). 562 CorelDRAW X5 The Official Guide FIGURE 1 9-4 Go for the subtle—or the dramatic—by changing the Depth setting on the extrude