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Thumbs up for Previews in AutoCAD

June 8, 2014

Have you ever looked at the drawing preview window or the view within the SSM (sheet set manager) and noticed that it does not display the correct drawing?  There is a quick fix. Go into Tools and Option (or right-click in the command area) and move to the Open and Save tab. There you will find a button for Thumbnail Preview Settings.

Figure 1: Open and Save Tab



Click the Thumbnail Preview Settings as shown above. Thumbnail previews are stored as PNG images, providing higher-quality thumbnail previews in a smaller file size. Image resolution is still controlled by the THUMBSIZE system variable.

We are now going to go through each section and explain what these variables and buttons control. Figure 2 shows the standard dialog box when selecting the Thumbnail Preview Settings.

Figure 2: Thumbnail Preview Setting Dialog Box

04-Thumbsave Window

The following list corresponds to the Red bullet numbers within Figure 2.

  1. The system variable that stores the thumbnail preview in the Windows registry is THUMBSAVE. This system variable replaces RASTERPREVIEW. By checking this box the variable is set to 1 and a preview will be generated.
  2. Defines the current view of the drawing as the home view.  A preview of the current view will be generated for the image.
  3. Resets the Home view back to default.
  4. Controls the updating of thumbnails for views and layouts.  These Settings are stored in the UPDATETHUMBNAIL system variable. The settings is stored as a bitcode using one of the following values.
0 Does not update previews
1 Updates previews for model space views
2 Updates previews for layout views
4 Updates previews for layouts
8 Updates previews when layouts or views are created, modified, or restored
16 Updates previews when the drawing is saved

These previews are displayed in the Sheet Set Manager. Sheet previews are displayed on the Sheet List tab, sheet view previews on the View List tab, and model space view previews on the Resource Drawings tab.

Hit OK and save your settings.  One last item you may want to check is when you are saving a drawing notice the update thumbnail check box right under your preview as shown in Figure 3a. If you HIT this and run a save on your drawing you will notice on the status bar that the previews are being generated.

 Figure 3a: Check that Preview Box


 You will notice when saving your drawing or saving an entire Sheet Set that the Previews will be updated as shown in Figure 3b. This may take a few seconds longer but it is worth the wait.

Figure 3b: Check that Preview Box



The background color, though, is taken from the drawing view when a drawing is saved. For the background to be saved as white in the thumbnail, the drawing needs to be on a white background when it is saved. The background color is selected on the Display tab in Options.

Note: if you are looking for more information on preview images in Widows explorer please visit R.K. McSwain’s blog CAD Panacea at  There are many instances in AutoCAD 2013 and 2014 where this can be corrected by changing a registry setting or even running a lisp routine at startup.  To check this go to a folder and set the list view to large thumbnails as shown in Figure 4.

Figure 4: Windows Explorer Views


Check your previews and give yourself a thumbs up!  The next person who loads the file(s) will be thankful you took the time to be sure the correct images are displayed when opening a drawing file.




From → CAD Tips

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