Using Raster, Vector, and Web Graphics - G-W Learning introduces using AutoCAD to work with raster and vector graphics fi les. This ... Chapter 30 Using Raster, Vector, and Web Graphics AutoCAD and

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<ul><li><p>Chapter 30 Using Raster, Vector, and Web Graphics AutoCAD and Its ApplicationsAdvanced 745Copyright by Goodheart-Willcox Co., Inc.</p><p> Chapter Chapter</p><p>Using Raster, Vector, and Web Graphics</p><p>Learning ObjectivesAfter completing this chapter, you will be able to:</p><p> Compare raster and vector fi les. Import and export raster fi les using AutoCAD. Import and export vector fi les using AutoCAD. Use image commands to manipulate inserted raster fi les. Create DWF, DWFx, and PDF fi les.</p><p>One of the important aspects of drawing in AutoCAD is the ability to share infor-mation. Generally, this means sharing drawing data and geometry between CAD soft-ware, either AutoCAD software installed on other workstations or software other than AutoCAD. AutoCAD creates drawing data fi les in a format known as a vector fi le. However, you can also share your work, as images, with photo editing and desktop publishing software. In Chapters 16 through Chapter 19, you learned how to create realistic scenes and render them to fi les. A scene rendered to a fi le is a raster image. However, raster images used in AutoCAD do not have to be created in AutoCAD. They may also come from digital photographs, scanned images, or Internet sources. This chapter introduces using AutoCAD to work with raster and vector graphics fi les. This includes importing, exporting, and setting various parameters.</p><p>Introduction to Raster and Vector Graphics </p><p>In the world of electronic imaging, there are two basic types of fi lesraster and vector. AutoCAD drawings are called vector graphics. A vector is an object defi ned by XYZ coor-dinates. In other words, AutoCAD stores the mathematical defi nition of an object. Pixels(picture elements) are the dots or bits in the monitor that make up the display screen. When drawing vector objects in AutoCAD, your monitor uses pixels to create a representa-tion of the object on the monitor. However, there is no relationship between the physical pixels in your monitor and a vector object. Pixels simply show the object at the current zoom percentage. Some common vector fi le formats are DWG, DXF, AI, and EPS.</p><p>Many illustrations created with drawing, painting, and presentation software are saved as raster fi les. A raster fi le creates a picture or image fi le using the location and color </p><p>IInttroodduccctiioonn tto RRasster aannd Vecttoorr GGGraapphhicss</p></li><li><p>Chapter 30 Using Raster, Vector, and Web Graphics AutoCAD and Its ApplicationsAdvanced 746Copyright by Goodheart-Willcox Co., Inc.</p><p>of the screen pixels. In other words, a raster fi le is made up of dots. Raster fi les are usually called bitmaps. There are several types of raster fi les used for presentation graphics and desktop publishing. Some common raster fi le formats include TIFF, JPEG, and GIF.</p><p>Working with Raster Files </p><p>Raster images inserted into AutoCAD drawings are treated much like externally referenced drawings (xrefs). Therefore, they are managed in the External Referencespalette. See Figure 30-1. This can be displayed with the EXTERNALREFERENCEScommand or by picking the dialog box launcher button at the lower-right corner of the Reference panel on the Insert tab of the ribbon.</p><p>Raster images are not added to the drawing database, but are attached and refer-enced by a path to the fi les location. Any changes to the image content must be made to the original fi le. Settings and commands in AutoCAD can, however, control the portion of the image shown and its appearance. Images can be inserted, removed, and modifi ed using commands found in the Reference panel in the Insert tab of the ribbon, Figure 30-2. These functions are discussed in detail in this section.</p><p>At the top of the External References palette is a drop-down list containing buttons for attaching drawing fi les (DWG fi les), image fi les, DWF fi les, DGN fi les, and PDF fi les. The File References area lists all fi les currently attached to the drawing, whether they </p><p>WWoorrkkingg wwiith RRastter FFillees</p><p>Type</p><p>EXTERNAL-REFERENCES</p><p>ERXREF</p><p>IMAGEIM</p><p>EX</p><p>TE</p><p>RN</p><p>AL</p><p>RE</p><p>FE</p><p>RE</p><p>NC</p><p>ES</p><p>Figure 30-1.The External References palette is used to manage attached images. The tooltip can be configured to display only the file name, a preview, details, or both a preview and details, as shown here.</p><p>Drop-down list for attaching drawings, images, and DWF files </p><p>Pick toshow a list</p><p>Pick to show a tree</p><p>Hover to showdetails and a </p><p>preview</p><p>Details of theselected image</p></li><li><p>Chapter 30 Using Raster, Vector, and Web Graphics AutoCAD and Its ApplicationsAdvanced 747Copyright by Goodheart-Willcox Co., Inc.</p><p>Figure 30-2.Image commands located on the Reference panel in the ribbon.</p><p>Attaches images, andother file types</p><p>Clips images</p><p>Changes brightness,fading, and contrast</p><p>Pick to display theExternal References palette</p><p>are drawings, images, or DWF, DGN, or PDF fi les. Right-clicking on an entry displays a shortcut menu that allows you to open, attach, unload, reload, and detach the fi le. If you hover the cursor over an entry in the palette, a preview window is displayed. By default, this preview provides details related to the fi le and a preview of the fi le.</p><p>There are many different types of raster fi les. Some raster fi les used in industry today are:</p><p> Tagged Image File Format (TIFF). A fi le format developed by Aldus Corporation and Microsoft Corporation. This is one of the most commonly used image fi le types.</p><p> Joint Photographic Experts Group (JPEG). A highly compressed graphics image fi le. This type of fi le is very common on websites. Also known as a JPG fi le.</p><p> Graphics Interchange Format (GIF). A fi le format developed to allow the exchange of graphic images over an online computer service, such as the Internet. This type of fi le, often animated, is sometimes found on websites.</p><p> Portable Network Graphics (PNG). Developed in the mid 1990s as a replace-ment for the GIF format. This fi le type is extensively used for electronic trans-mission, such as via e-mail or as website graphics.</p><p>Other raster fi le types can also be imported into AutoCAD. If you have a raster image that cannot be directly imported, you will need to fi rst import the fi le into a paint or draw program. Then, export the image in a format that AutoCAD can read.</p><p>Inserting Raster ImagesThe IMAGEATTACH command is used to attach an image fi le to a drawing. When </p><p>the command is selected, the Select Reference File dialog box is displayed. Next, navi-gate to the folder containing the raster fi le, select the fi le, and pick Open. This displays the Attach Image dialog box, Figure 30-3. When the OK button is picked and the image placed, it is displayed in the drawing area. See Figure 30-4.</p><p>The image name is displayed at the top of the dialog box. You can choose to save the full path, a relative path, or no path. The type of path is selected in the Path type drop-down list.</p><p>A full path specifi es the complete location of the image fi le, such as c:\images\building.tif. If the image fi le is moved from this location, AutoCAD cannot fi nd it.</p><p>A relative path specifi es the location of the image fi le based on the location of the drawing fi le. For example, the path .\images tells AutoCAD that the image fi le is located in a subfolder (named images) of the folder where the drawing is located. The entry ..\images tells AutoCAD to look for the fi le by moving up one folder from where the drawing is stored and then in the subfolder \images. The entry ..\..\images tells AutoCAD to move up two folders and then look in the subfolder \images. The current drawing must be saved in order to specify a relative path.</p><p>Ribbon</p><p>Insert &gt; Reference</p><p>Attach</p><p>Type</p><p>ATTACHIMAGEATTACH</p><p>IAT</p><p>IMA</p><p>GE</p><p>AT</p><p>TAC</p><p>H</p></li><li><p>Chapter 30 Using Raster, Vector, and Web Graphics AutoCAD and Its ApplicationsAdvanced 748Copyright by Goodheart-Willcox Co., Inc.</p><p>Figure 30-3.The image name and path are displayed in the Attach Image dialog box. Be sure to select the type of path to use. The dialog box expands to include the Image Information area when the Show Details button is picked.</p><p>Actualpath</p><p>Paththat willbe saved</p><p>Picking this button toggles thedisplay of the lower portion</p><p>Select thetype of path</p><p>Figure 30-4.The raster image attached to an AutoCAD drawing.</p></li><li><p>Chapter 30 Using Raster, Vector, and Web Graphics AutoCAD and Its ApplicationsAdvanced 749Copyright by Goodheart-Willcox Co., Inc.</p><p>The no path option tells AutoCAD that the image is located in the same folder as the drawing. If the image fi le is not found in that folder, AutoCAD looks in the path specifi ed by the PROJECTNAME system variable, then in the support fi le search path defi ned in the Files tab of the Options dialog box.</p><p>The path to the image fi le is displayed at the bottom of the Image Information area. Also displayed is the path that will be saved in the drawing. The Image Informationarea is displayed by picking the Show Details button at the bottom of the dialog box.</p><p>You can preset image parameters (insertion point, scale, and rotation) or choose to specify them on-screen. Image resolution information is displayed in the Image Information area of the expanded dialog box. Refer to Figure 30-3.</p><p>PROFESSIONAL TIP</p><p>If you are working on a project that uses xrefs and attached images, adding a project subfolder below the folder where the drawings are stored may be benefi cial. Then, use relative paths when inserting images or xrefs. This allows all related fi les for a project to be found by AutoCAD, even if the folder structure is moved to a different drive or root folder.</p><p>Managing Attached ImagesAs stated earlier, the External References palette is used to control the raster images </p><p>inserted into a drawing. When you hover over the fi le name in the File Referencesarea, the preview window displays the image name, its status (loaded or unloaded), fi le size, type, date the image was last saved, and the saved path. Refer to Figure 30-1.</p><p>Right-clicking on the image name displays a shortcut menu containing options to help you manage the image. The fi ve options are:</p><p> Open. This opens the image in the program associated with the fi le type of the image. For example, if Microsoft Photo Editor is associated with the TIFF fi le type, the TIFF image is displayed in this program.</p><p> Attach. This opens the Attach Image dialog box, discussed in the previous section, for attaching an additional image to the drawing.</p><p> Unload. Unloads the selected image, but retains its path information. The Status column displays Unloaded if this option is selected. Display the list view to see the columns. An unloaded image is displayed as a frame until reloaded.</p><p> Reload. Reloads the selected image fi le. Detach. Removes, or detaches, the selected image fi le from the drawing.Right-clicking in the File References area, but not on a fi le name, displays a </p><p>different shortcut menu. See Figure 30-5. This shortcut menu contains 10 options: Reload All References. Reloads any fi les attached to the current drawing. Select All. Selects all of the fi les listed in the File References area. Attach DWG. Allows you to attach other drawings as xrefs.</p><p>TIPTIP</p><p>Figure 30-5.The tooltip in the External References palette can be configured to display various information. The settings are located in this shortcut menu.</p></li><li><p>Chapter 30 Using Raster, Vector, and Web Graphics AutoCAD and Its ApplicationsAdvanced 750Copyright by Goodheart-Willcox Co., Inc.</p><p> Attach Image. Allows you to attach additional images. Attach DWF. Allows you to attach a DWF fi le as an xref. Attach DGN. Allows you to attach a DGN fi le (MicroStation drawing) as an xref. Attach PDF. Allows you to attach a PDF (Adobe Acrobat) fi le. Tooltip Style. The tooltip (help text) that appears when you hover over one of the </p><p>items is customizable. The tooltip can display the fi le name only, a preview only in the size you select, fi le details (including the name), or details and a preview.</p><p> Preview/Details Pane. Turns on or off the pane at the bottom of the External References palette. If the tooltip is set to display details and a preview, you probably will not need to display the preview/details pane.</p><p> Close. Closes the External References palette.</p><p>PROFESSIONAL TIP</p><p>If drawing-regeneration time is becoming long, unload attached image fi les that are not needed for the current drawing session. </p><p>Controlling Image File DisplaysOnce an image is attached to the current drawing, its display can be adjusted if </p><p>needed. The IMAGECLIP, IMAGEADJUST, IMAGEQUALITY, and TRANSPARENCY commands are used to do so. These commands are discussed in this section. All of these commands (except IMAGEQUALITY) are available in the Image contextual tab. This tab is displayed in the ribbon when the border of the image is selected. See Figure 30-6.</p><p>Clipping an ImageThe IMAGECLIP command allows you to trim away a portion of the image that </p><p>does not need to be seen. The clipping frame, also called a clipping path, can be rect-angular or polygonal. By default, the IMAGECLIP command removes portions of the image outside of the boundary. You can remove portions inside of the boundary with the Invert Clip option.</p><p>Select the IMAGECLIP command and then select the image to clip. Then, select the New boundary option. When the Rectangular option is selected, you are prompted to pick a fi rst and opposite corner. The image outside of the rectangular frame is hidden. If the command was accessed from the Image contextual tab, the image is selected and grips are displayed at the corners with an arrow grip on </p><p>TIPTIP</p><p>Ribbon</p><p>Image &gt; Clipping</p><p>Create Clipping Boundary</p><p>Type</p><p>IMAGECLIPCLIPICL</p><p>IMA</p><p>GE</p><p>CL</p><p>IP</p><p>Figure 30-6.The Image contextual tab is displayed in the ribbon when an image is selected.</p><p>Add aclipping path</p><p>Remove aclipping path</p><p>Toggle the displayof the image</p><p>Change theimage transparency</p><p>Settingsfor adjusting</p><p>the image</p></li><li><p>Chapter 30 Using Raster, Vector, and Web Graphics AutoCAD and Its ApplicationsAdvanced 751Copyright by Goodheart-Willcox Co., Inc.</p><p>the left-hand edge. Pick and drag the corner grips to change the size of the clip boundary. Picking the arrow grip inverts what is hidden. This is the same as using the Invert Clip option.</p><p>The Polygonal option allows you to construct a clipping frame composed of three or more points. Simply pick points until the area to be clipped is completely surrounded and then press [Enter]. The image outside of the polygonal frame is hidden. The grips function the same as they do with a rectangular boundary. Figure 30-7 shows the results of using the Rectangular and Polygonal options of the IMAGECLIP command on a raster image. Three additional options of IMAGECLIP allow you to work with the display of the clipped image.</p><p> ON. Turns the clipping frame on to display only the clipped area. OFF. Turns off the clipping frame to display the entire original image and frame. Delete. Deletes the clipping frame and displays the entire original image. </p><p>Selecting Remove Clipping from the Image contextual tab after a clipped image is selected does the same thing.</p><p>You can pick an unclipped image frame to display...</p></li></ul>


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