Architects, engineers, and facilities planners often need to know the square footage of a room or a section of a building. A structural engineer might want to find the cross-sectional area of a beam. In this section, you'll practice determining the areas of regular objects.

First you'll determine the square-foot area of the living room and entry of your studio unit plan:

The number of points you can pick to define an area is limitless, so you can obtain the areas of complex shapes. Use the Blipmode feature to keep track of the points you select so you know when you come to the beginning of the point selections.

Find the Coordinate of a Point or a Distance in a Drawing

To find absolute coordinates in a drawing, use the ID command. Click the ID Point tool on the Home tab's expanded Utilities panel, or type ID

To find the distance between two points, choose Distance from the Measure flyout on the Home tab's Utilities panel, or type Dist

Hatch patterns are used primarily to add graphics to your drawing, but they can also serve as a means to finding areas. You can use any hatch pattern you want because you're interested in only the area it reports back to you. You can also set up a special layer devoted to area calculations and then add the hatch patterns you use to find areas to this layer. That way, you can turn off the hatch patterns so they don't plot, or you can turn off the Plot setting for that layer to ensure that it doesn't appear in your final output.

To practice using hatch patterns to find an area, do the following:

If you need to recall the last area calculation value you received, enter ′Setvar

The Hatch command creates a hatch pattern that conforms to the boundary of an area. This feature, combined with the ability of the Measuregeom command to find the area of a hatch pattern, makes short work of area calculations. Another advantage of using hatch patterns is that, by default, hatch patterns avoid islands within the boundary of the area you're trying to find.

The area of a hatch pattern is also reported by the Properties palette. Select the hatch pattern whose area you want to find, and then right-click and select Properties. Scroll down to the bottom of the Geometry group, and you'll see the Area listing for the hatch pattern you selected. You can select more than one hatch pattern and find the cumulative area of the selected hatch patterns in the Properties palette.

Hatch patterns work extremely well for finding areas, but if you find that for some reason you can't use hatch patterns, you have another alternative. You can still use a command called Boundary to generate a polyline outline of an enclosed boundary and then obtain the area of the outline using the Measuregeom command (Measure on the Home tab's Utilities panel). If islands are present within the boundary, you have to use the Subtract feature of the Measuregeom command to remove the area of the island from the overall boundary area. In this section, you'll use the example of the flange part, which contains two islands in the form of the two circles at the lower end (see Figure 20.3).

Figure 20.3. A flange to a mechanical device

By using the Add and Subtract options of the Measuregeom command, you can maintain a running total of several separate areas being calculated. This gives you flexibility in finding areas of complex shapes. This section guides you through the use of these options.

For the following exercise, you'll use a flange shape that contains circles. This shape is composed of simple arcs, lines, and circles. Use these steps to see how you can keep a running tally of areas:

In this exercise, you first selected the main object outline and then subtracted the island objects. You don't have to follow this order; you can start by subtracting areas to get negative area values and then add other areas to come up with a total. You can also alternate between Add and Subtract modes, in case you forget to add or subtract areas.

You may have noticed that the Measuregeom Command prompt offered Specify first corner point or [Object/Add/Subtract/eXit]: as the default option for both Add and Subtract modes. Instead of using the Object option to pick the circles, you can start selecting points to indicate a rectangular area, as you did in the first exercise in this chapter.

Whenever you press

As you can see from these exercises, it's simpler to outline an area first with a polyline wherever possible and then use the Object option to add and subtract area values of polylines.

In this example, you obtained the area of a mechanical object. However, the same process works for any type of area you want to calculate. It can be the area of a piece of property on a topographical map or the area of a floor plan. For example, you can use the Object option to find an irregular shape such as the one shown in Figure 20.5, as long as it's a polyline.

Figure 20.5. The site plan with an area to be calculated

The Measuregeom command offers a number of other options for measuring your drawing. The options appear in the Command window as [Distance/Radius/Angle/ARea/Volume/eXit] or at the cursor as a Dynamic Input option. These options are automatically selected when you click the related tool from the Measure flyout on the Utilities panel. Remember that to use an option, type the capitalized letter or letters of the option shown in the list. Table 20.1 gives you descriptions of the options and how they are used.

Table 20.1. The Measuregeom Command Options

Option	Use
Distance	Returns the distance between two points. Type D
Radius	Returns the radius of an arc or circle. Type R
Angle	Returns the angle of an arc or the angle between two lines. Type A
ARea	Returns the area of a set of points or boundary. Type AR
Volume	Returns the volume of an area. Type V
eXit	Exits the current option or the Measuregeom command. You can also press the Esc key.

When you work with a group of people on a large project, keeping track of a drawing's setup becomes crucial. You can use the Status command to obtain general information about the drawing you're working on, such as the base point, current mode settings, and workspace or computer memory use. The Status command is especially helpful when you're editing a drawing someone else has worked on because you may want to identify and change settings for your own style of working. Click Drawing Utilities

Figure 20.6. The Status screen of the AutoCAD Text Window

Here is a brief description of each item on the Status screen. Note that some of the items you see on the screen will vary somewhat from what I've shown here, but the information applies to virtually all situations except where noted:

When you're in Paper Space, the Status command displays information regarding the Paper Space limits. See Chapter 16 for more on Model Space and Paper Space.

In addition to being useful in understanding a drawing file, the Status command is an invaluable tool for troubleshooting. Frequently, a technical support person can isolate problems by using the information provided by the Status command.

The Time command enables you to keep track of the time spent on a drawing for billing or analysis purposes. You can also use the Time command to check the current time and find out when the drawing was created and most recently edited. Because the AutoCAD timer uses your computer's time, be sure the time is set correctly in Windows.

To access the Time command, enter Time

Figure 20.7. The Time screen in the AutoCAD Text Window

The first four lines of this message tell you the current date and time, the date and time the drawing was created, and the last time the drawing was saved.

The fifth line shows the total time spent on the drawing from the point at which the file was opened. This elapsed timer lets you time a particular activity, such as changing the width of all the walls in a floor plan or redesigning a piece of machinery. The last line tells you when the next automatic save will be.

You can turn the elapsed timer on or off or reset it by entering ON, OFF, or Reset at the prompt shown at the bottom of the message. Or press

If you've been working through this book's ongoing studio apartment building tutorial, you'll have noticed that I've occasionally mentioned a system variable in conjunction with a command. You can check the status or change the setting of any system variable while you're in the middle of another command. To do this, you type an apostrophe (′) followed by the name of the system variable at the Command prompt.

For example, if you start to draw a line and suddenly decide you need to rotate your cursor 45°, you can do the following:

You can also recall information such as the last area or distance calculated by AutoCAD. Type Setvar

Many system variables give you direct access to detailed information about your drawing. They also let you fine-tune your drawing and editing activities. In Appendix D, you'll find all the information you need to familiarize yourself with the system variables. Don't feel that you have to memorize them all at once; just be aware that they're available.

At times, you may find it helpful to keep a log of your activity in an AutoCAD session. A log is a text file containing a record of your activities. It can also contain notes to yourself or others about how a drawing is set up. Such a log can help you determine how frequently you use a particular command, or it can help you construct a macro for a commonly used sequence of commands.

The following exercise demonstrates how to save and view a detailed record of an AutoCAD session by using the Log feature:

As a shortcut, you can quickly turn the Maintain A Log File feature on and off by typing Logfileon

Finding the Log File

If you can't find the log file for the current drawing, you can enter logfilename

If you're working in groups, it's often helpful to have a record of the status, editing time, and system variables for particular files readily available to other group members. It's also convenient to keep records of block and layer information so you can see whether a specific block is included in a drawing or what layers are normally on or off.

You can use the Windows Clipboard to capture and save such data from the AutoCAD Text Window. The following steps show you how it's done:

If you want to copy only a portion of the AutoCAD Text Window to the Clipboard, perform the following steps:

Although you used the AutoCAD Text Window to copy text in this exercise, you can also copy from the docked command line at the bottom of the AutoCAD window.

You may notice four other options on the shortcut menu: Recent Commands, Paste, Paste To CmdLine, and Options. Choosing Recent Commands displays a list of the most recent commands. For most activities, you'll use a handful of commands repeatedly; the Recent Commands option can save you time by giving you a shortcut to those commands you use the most. The Paste options paste the first line of the contents of the Clipboard into the command line or input box of a dialog box. This can be useful for entering repetitive text or for storing and retrieving a frequently used command. Choosing Options opens the Options dialog box.

Items copied to the Clipboard from the AutoCAD Text Window can be pasted into dialog box input boxes. This can be a quick way to transfer layers, linetypes, or other named items from the AutoCAD Text Window into dialog boxes. You can even paste text into the drawing area.

As you start to build a library of AutoCAD files, you'll have to start thinking about how to manage them. Keeping track of AutoCAD files can be a daunting task. Most AutoCAD users start to name files by their job number to keep things organized. But even the best organization schemes don't help if you need to find that one special file among thousands of files in your library. In this section, you'll learn how to include information in an AutoCAD file that you can use later to locate the file by using the Windows Search utility.

AutoCAD includes the DesignCenter, a tool that can help you locate a file more easily based on a keyword or description. Chapter 29 contains a complete discussion of the DesignCenter.

Figure 20.8. A drawing's Properties

Here are descriptions of the four tabs in this dialog box:

After you've included information in a file's Properties dialog box, you can use the AutoCAD DesignCenter, the File dialog box, or the Windows Search function to locate your file.

This option opens a Find dialog box that works just like the Windows XP Search Results window.

No system is perfect. Eventually, you'll encounter a file that is corrupted in some way. Two AutoCAD tools can frequently salvage a corrupted file:

You can access these tools from the Drawing Utilities option on the Application menu. More often than not, these tools will do the job, although they aren't a panacea for all file-corruption problems. In the event that you can't recover a file even with these tools, make sure your computer is running smoothly and that other systems aren't faulty.

If for some reason your computer shuts down while you're in the middle of editing a file, you'll see the Drawing Recovery Manager the next time you start AutoCAD. The Drawing Recovery Manager lets you recover the file you were working on when AutoCAD unexpectedly shut down. This feature works just like the file-recovery feature in Microsoft Office: A panel appears to the left of the AutoCAD Text Window showing you a list of recoverable files. You can then select the filename from the panel to open the file. You can find the Drawing Recovery Manager in the Application menu under Drawing Utilities

To export your current drawing as a DXF file, follow these steps:

In step 3, you can select from the following DXF file formats:

Choose the format appropriate to the program you're exporting to. In most cases, the safest choice is AutoCAD R12/LT2 DXF if you're exporting to another CAD program, although AutoCAD won't maintain the complete functionality of AutoCAD 2009 for such files.

After you've selected a DXF format from the Files Of Type drop-down list, you can set more detailed specifications by choosing Tools

Figure 20.9. The DXF save-as options

The DXF Options tab contains the following options:

In addition to using the Save Drawing As dialog box, you can type Dxfout

Some offices have made the DXF file format their standard for CAD drawings. This is most commonly seen in offices that use a variety of CAD software besides AutoCAD.

AutoCAD can be set up to read and write DXF files instead of the standard DWG file format by default. Here's how it's done:

After you do this, all your drawings are automatically saved in the DXF format of your choice.

You can also set the default AutoCAD file type by clicking the Options button in the Save Drawing As dialog box. As you saw in the preceding section, the Saveas Options dialog box includes the DWG Options tab (Figure 20.10). You can select a default file type from the Save All Drawings As drop-down list.

Figure 20.10. The DWG save-as options

If you need to open a DXF file only once in a while, you can do so by selecting DXF from the Files Of Type drop-down list in the Select File dialog box. This is the dialog box you see when you click Open from the Quick Access toolbar. You can also use the Dxfin command:

In some cases, you may need only a rough image of your AutoCAD drawing. You can export your drawing as a raster file that can be read in virtually any page-layout and word-processing program. To do this, you need to use the PublishToWebJPG.pc3 or PublishToWebPNG.pc3 printer option that comes with AutoCAD. To use it, do the following.

If you don't see a "paper size" you want to use, you can create a custom size using the Properties button in the Plot dialog box:

You can edit these settings at any time by opening the PC3 file in the Application DataAutodeskAutoCAD 2010R18.0enuPlotters subfolder of your profile folder. You can access this file through Windows Explorer or from AutoCAD by clicking Plotter Manager from the Output tab's Plot panel.

To create a raster file version of your drawing, click Plot from the Quick Access toolbar. Then, in the Plot dialog box, select your raster file plotter configuration from the Name drop-down list of the Printer/Plotter group. You can then proceed to plot your drawing, but instead of paper output, you'll get a raster file. You can specify the filename and location when you click the OK button to plot the file.

If you need to make changes to your raster file configuration, click Plotter Manager from the Output tab's Plot panel. Then, in the Plotters window, double-click your raster file configuration file. You'll see the same Plotter Configuration Editor you used to set up the raster plotter configuration.

You can set up a different plotter configuration for each type of raster file you use. You can also set up plotter configurations for different resolutions if you choose. To learn more about plotting in general, see Chapter 8. Appendix C provides detailed information on the Plotter Configuration Editor.

If you need to preserve the accuracy of your drawing, or if you want to take advantage of TrueType or PostScript fonts, you can use the DXF, Windows Metafile (WMF), or PostScript vector format. You can also export to DGN and SAT file formats. Intergraph's DGN format is popular in civil engineering, mapping, and other CAD applications. The SAT format is associated with ACIS and is a 3D modeling format.

For vector-format files, DXF is the easiest to work with, and with TrueType support, DXF can preserve font information between AutoCAD and page-layout programs that support the DXF format. The WMF format is also a commonly accepted file format for vector information, and it preserves TrueType fonts and lineweights used in your drawings.

PostScript is a raster/vector hybrid file format that AutoCAD supports. Unfortunately, AutoCAD dropped direct PostScript font support with Release 14. However, you can still use substitute fonts to stand in for PostScript fonts. These substitute fonts are converted to true PostScript fonts when AutoCAD exports the drawing. You don't see the true results of your PostScript output until you print your drawing on a PostScript printer.

The DXF file export was covered in a previous section of this chapter, so the following sections will concentrate on the WMF and PostScript file formats.

PostScript Output

AutoCAD can export to the Encapsulated PostScript (EPS) file format. If you're using AutoCAD 2010, you can obtain PostScript output in two ways: You can choose Export

To set up AutoCAD to plot your drawing to an EPS file, follow these steps:

1. Choose Print

   

2. Choose Next on the Introduction screen.

3. On the Begin screen of the Add-A-Plotter Wizard, choose My Computer.

4. On the Plotter Model screen, select Adobe from the Manufacturers list, and then select the appropriate PostScript level from the Models list.

5. Skip the Import PCP Or PC2 screen and the Ports screen.

6. Enter a name for your EPS output settings on the Plotter Name screen.

7. On the Finish screen, click the Finish button.

AutoCAD doesn't preserve font information when creating EPS files from the printer option. It also produces larger files, especially if your drawing contains a lot of area fills and filled fonts. As an alternative to EPS, you can "plot" to an Adobe PDF file. EPS files can often be substituted with PDF files. You'll need to install the Autodesk-provided PDF plotter driver using the Add-A-Plotter Wizard described earlier. When you get to the Plotter Model screen, select the Autodesk ePlot (PDF) option from the Manufacturers list. You can also use the full version of Adobe Acrobat or Acrobat Pro to produce PDF files from AutoCAD.

The HPGL plot-file format is another vector format you can use to export your AutoCAD drawings. Use the method described earlier in the section "Exporting Raster Files" to add the HPGL plotter driver to your printer/plotter configuration.

Using Autocad Dwf Files

The Autodesk DWF file format is another format you can use to exchange drawing data with others. It offers features that are geared toward AutoCAD users. You can import DWF files as external references, and, using a free DWF viewer, you can gather information about a drawing such as block information, attribute data, and distance measurements. See Chapter 29 for more on DWF.

After you've pasted an object with links, you can control the links by typing Olelinks

Figure 20.15. Editing links

The options available in the Links dialog box are as follows:

Although it can be beneficial to import worksheets as linked OLE objects, you may prefer to import worksheets as AutoCAD entities. You may not need the direct link to the source material that OLE linking offers. The ability to edit the imported worksheet directly in AutoCAD may have a higher priority for you.

In Chapter 11, you saw how you could create tables in AutoCAD by using the Table tool. You can import an Excel worksheet as an AutoCAD table by using the AutoCAD Entities option in the Paste Special dialog box. By importing worksheets as tables, you have more control over the layout and appearance of the worksheet data.

Try the following exercise to see how you can create a table from a worksheet:

You can edit this imported worksheet using the editing methods for AutoCAD tables described in Chapter 11. In that chapter, you learned that you can edit the text format, the border lineweight and color, and the background of cells. You can add rows and columns and rotate text so that it fits more uniformly in a vertical column.

In this exercise, the worksheet was imported using the default standard table style. This gives you a simple-looking table using the AutoCAD Txt font. You can set up a custom table style with the fonts and borders you want and then import the table for a more custom appearance. Make sure your custom table style is the current style before you import the worksheet.

The Paste Special dialog box offers several other options that may better suit your needs. Here is a brief description of each format that is available:

The options you see in the Paste Special dialog box depend on the type of data being imported. You saw how the Microsoft Excel Worksheet option maintains the imported data as an Excel worksheet. If the contents of the Clipboard come from another program, you're offered that program as a choice in place of Excel.

Just as you can cut and paste data into AutoCAD from applications that support OLE, you can also cut and paste AutoCAD images to other applications. This can be useful as a way of including AutoCAD images in word-processing documents, worksheets, or page-layout program documents. It can also be useful in creating background images for visualization programs such as Autodesk's 3D Studio Max and VIZ and for paint programs such as Corel Painter.

If you cut and paste an AutoCAD drawing to another file by using OLE and then send the file to someone using another computer, they must also have AutoCAD installed before they can edit the pasted AutoCAD drawing.

The receiving application doesn't need to support OLE, but if it does, the exported drawing can be edited with AutoCAD and will maintain its accuracy as a CAD drawing. Otherwise, the AutoCAD image will be converted to a bitmap graphic.

In the receiving application, choose Edit