Open and Save Settings
The Open and Save tab controls a variety of features associated with opening and saving files. By editing the features, you can control the format AutoCAD saves files as, whether AutoCAD automatically saves files, and whether AutoCAD makes a backup copy when it saves a file. These, and other related features, are discussed in this section.
The Open and Save tab is organized into five areas, as shown in Figure 3.8. The five areas are as follows:
Figure 3.8. The Open and Save tab in the Options dialog box controls how AutoCAD handles files.
File Save. Controls various features associated with saving files.
File Safety Precautions. Controls elements dealing with automatically saving backup files.
File Open. Controls number of recently used drawing files to list and full path display in the title bar area of the drawing.
External References (Xrefs). Controls several features associated with external references.
ObjectARX Applications. Controls several features associated with AutoCAD’s Runtime Extension (ARX) files.
File Save
In the File Save area, you control the type of file AutoCAD saves the current drawing as, whether a thumbnail image is saved with the drawing, and AutoCAD’s incremental save percentage.
AutoCAD provides several different file types to save the current drawing as. These file types represent the default file types and can be overridden using the Save As command from the File menu. The file types include .DWG formats for AutoCAD 2000, and for Release 14 and 13, AutoCAD’s Drawing Template Format (.DWT), and .DXF formats for AutoCAD 2000, as well as Releases 14, 13, and 12.
You also control whether AutoCAD saves a thumbnail image with the current drawing. By toggling on this option, AutoCAD snaps an image of the current drawing’s display, and saves it with the drawing. When opening an existing drawing, the image appears in the Select File dialog box when you select the drawing’s filename. This feature is useful for visually identifying a drawing without opening it. This thumbnail image is not saved in .DXF format files.
Finally, you can set the percent value for AutoCAD’s Incremental Save Percentage feature. This feature controls the frequency at which AutoCAD performs a full save when saving a file. Performing a full save removes wasted space from the drawing’s database, which reduces a drawing’s file size. The percent value refers to the amount of wasted space that is allowed in the drawing’s database. After the percentage of allowable wasted space is reached, AutoCAD performs a full save, removing the wasted space.
The advantage of this feature is that if you make small modifications to your drawing and frequently save the drawing, you do not spend a lot of time waiting for AutoCAD to finish a full save. The disadvantage is that because AutoCAD does not perform a full save each time it saves a drawing, the drawing’s file size is larger than necessary because the wasted space is not removed. Generally speaking, the default value of 50% is adequate for most users’ needs. However, if your drawing’s file size is too large and consuming too much disk space, reduce the number to 25% to make file sizes smaller. Reducing the number to below 20% optimizes drawing file sizes, but degrades performance when saving drawings because full saves are performed much more frequently.
Note
The Incremental Save Percentage feature does not affect how much data is saved. AutoCAD always saves all data, including edits, during an incremental save. What AutoCAD does not do during an incremental save is remove wasted space, which makes the .DWG file as small as possible. Therefore, if AutoCAD crashes, even though your last save was an incremental save, all data is retained. The only data lost is the new edits performed since your last save.
File Safety Precautions
In the File Safety Precautions area, AutoCAD provides tools for helping you avoid data loss and for detecting errors in drawings. The following list gives you an overview of these features:
Automatic Save. Controls whether AutoCAD saves the current drawing automatically, and how frequently it does so. Enter the Save Frequency value in minutes and AutoCAD will automatically save the current drawing when the time limit is reached, after which it starts tracking the time from zero.
Create Backup Copy with Each Save. When this feature is on, AutoCAD saves the current drawing, then makes a backup copy (.BAK). Generally, it’s a good idea to let AutoCAD save a backup copy of your drawing. However, bear in mind that the backup file is just as large as the drawing file, which can consume a lot of disk space.
Full-Time CRC Validation. This option specifies whether a cyclic redundancy check (CRC) should be performed each time an object is read into the drawing. CRC is an error-checking mechanism. If your drawings are being corrupted and you suspect a hardware problem or AutoCAD error, turn on this option.
Maintain a Log File. Controls whether AutoCAD saves the contents of the text window to a log file. This feature is useful if you need to retrace the command performed during an editing session. This file can also get very large.
File Extension for Temporary Files. This feature controls the file extension AutoCAD uses for the temporary files it creates during an editing session. The default extension is .ac$, and generally is adequate. When an AutoCAD editing session is ended improperly, AutoCAD does not have the opportunity to remove temporary files. Consequently, you must search your system for files ending with the designated extension, and remove them.
Note
You define the location where AutoCAD stores temporary files in the Files tab, in the Temporary Drawing File Location folder.
File Open
The File Open is a feature added in AutoCAD 2000i and contains only two controls. First is for the number of recently used drawing files to list in the File pull-down menu. The default setting is 4 but you will find increasing this to be very helpful. The other control is for whether or not to display the full file path for drawings, along with their name, in the title area. This is especially useful if you work in an environment with many projects but similar drawing names. See Figure 3.8 for where this is located.
External References (Xrefs)
In the External References (Xrefs) area, AutoCAD enables you to control demand loading, retain modifications to xref-dependent layers, and allow the current drawing to be edited from another drawing.
The Demand Load Xrefs feature allows you to disable demand loading, enable demand loading, or enable demand loading with copy. Demand loading is discussed in detail in Chapter 14.
The Retain Changes to Xref Layers option allows you to save the current state of xref-dependent layers in the current drawing. Layer states such as Freeze/Thaw and On/Off can be changed in the current drawing for xref-dependent layers. By toggling on this option, changes made to the layer states are saved, and retained when the drawing is opened again.
The Allow Other Users to Refedit Current Drawing option controls whether the current drawing can be edited when it is attached as an xref. This toggles off or on the command inline reference editing feature introduced in AutoCAD 2000, and is discussed in detail in Chapter 14, “Working with Drawings and External Drawings Productively.”
ObjectARX Applications
The ObjectARX Applications area allows you to control settings that relate to AutoCAD Runtime Extension (ARX) applications and proxy graphics.
The Demand Load ARX Apps feature specifies if and when AutoCAD demand-loads a third-party application if a drawing contains custom objects created in that application. Demand loading means AutoCAD loads the application in the current drawing session in order to display the custom object(s). This feature has four options:
Custom Object Detect. Demand-loads the source application when you open a drawing that contains custom objects. This setting does not demand-load the application when you invoke one of the application’s commands.
Command Invoke. Demand-loads the source application when you invoke one of the application’s commands. This setting does not demand-load the application when you open a drawing that contains custom objects.
Object Detect and Command Invoke. Demand-loads the source application when you open a drawing that contains custom objects or when you invoke one of the application’s commands.
The Proxy Images for Custom Objects feature controls the display of custom objects in drawings. Proxy images are created when you open a drawing that contains custom objects, but you do not have access to the application that created the objects. Because AutoCAD cannot properly display the objects with the application, it creates a place holder called a Proxy Object. This feature has three options:
Do Not Show Proxy Graphics. Specifies to not display proxy objects in drawings.
Show Proxy Graphics. Specifies to display proxy objects in drawings.
Show Proxy Bounding Box. Specifies to show a box in place of custom objects in drawings.
The Show Proxy Information Dialog Box option specifies whether AutoCAD displays a warning when you open a drawing that contains custom objects. The dialog box provides the total number of proxy objects in the drawing (both graphical and non-graphical), the name of the missing application, and additional information about the proxy object type and display state.