Learn the intricacies of the AutoCAD Scale tool's Reference option in this detailed tutorial, including how to use it to match object dimensions and make a vase of a specific height.
This exercise is excerpted from Noble Desktop’s past AutoCAD training materials and is compatible with Photoshop updates through 2020. To learn current skills in AutoCAD, check out AutoCAD Bootcamp and AutoCAD classes in NYC and live online.
Topics Covered in This AutoCAD Tutorial:
Intro to the Scale Tool’s Reference Option, Using the Scale Tool’s Reference Option
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Exercise Overview
The Reference option in the Scale command can match the height of an object to that of another object. The vase shown in the image above was created in Adobe Ilustrator and exported as an AutoCAD DWG file. Adobe Illustrator is better for drawing organic artistic shapes like this, but is not as focused on precision as AutoCAD. In this exercise, we will use the Reference option on the Scale tool to make the vase a specific height.
Intro to the Reference Option on the Scale Tool
With this option in the Scale tool 
, you can make the dimensions of objects match specific measurements rather than enter a Scale Factor. You can match the height or width of preexisting objects or create “dummy” objects for reference and delete them afterwards. After establishing the Base Point, the Reference option will appear in the Command Line. If you choose it, you will click two points, usually on the object itself. The two points will form a reference line that you can size with your mouse, and the object scaling will match the scaling of the line. You can use Object Tracking to match the length of the reference line to other objects. You may also use the Reference option because it will allow you to precisely scale with the mouse rather than entering a Scale Factor.
Making the Vase a Specific Height Using the Reference Option
Open the file Scale-Vase.dwg.
This file was created in Adobe Illustrator, so if you see a dialog box stating the file did not originate in AutoCAD, click Continue opening DWG file to open the drawing.
Start the Scale command and select the vase. Place the Base Point at the endpoint in the middle of the bottom edge of the vase. There is both an Endpoint and a Midpoint in the same location, but just the Endpoint symbol will appear.
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Press R Enter to select the Reference option. Click on the endpoint in the middle of the bottom edge of the vase, the same as the Base Point to establish the first reference point. Click on the Midpoint of the top edge of the vase for the second reference point.
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To specify the new reference length, click on the top endpoint of the green reference line, as shown in the screenshot below. The vase will be the same height as the reference line.
Delete the reference line.