Shift Modifier: Trim and Extend

The TRIM and EXTEND commands are some of the most used commands in AutoCAD and AutoCAD vertical products that allow us to extend one object to another, and likewise, trim one object to another. These two commands are direct inverse version of one another, and as such are very similar to each other in their workflows. Many AutoCAD users that I speak with use these commands independently to accomplish various tasks. 

In the figure below, two (2) line segments are shown which need to be cleaned up by extending the line on the right to the line on the left. Once the right line has been extended to the line on the left, the left line will then need to be trimmed to the line on the right. Typically, this is done in two parts using the respective command.

Figure 1: Corner Clean-up Required

I wanted to create this blog post to bring to your attention another way to handle this workflow to minimize the steps involved. After extending the line on the right using the EXTEND command, hold Shift on your keyboard to swap the functionality of the EXTEND command to trim the line on the left. Holding shift while the EXTEND or TRIM command is active will change the functionality of your current command with the other. This process is represented in the images below.

Figure 2: Extend Command to Extend the Right Line Segment

Figure 3: Shift Held while Extend Command Active to Trim the Right Line Segment

Figure 4: The Final Result Using Only the Extend Command

Holding Shift while in the EXTEND or TRIM command to call on the inverse functionality is a great way to speed up efficiency within AutoCAD, saving you time by not needing to exit a command and execute a new one. 

One last comment on the task shown outlined in this blog; Make sure to check out my other article titled Shift Modifier: Fillet. This article will explain another way to handle this task without using TRIM or EXTEND to speed up this task even more!

About the Author

Archie Dodge

Civil Solutions Applications Expert<br><br>Over 12 years of experience in geotechnical engineering design, and land planning design, ranging in projects from dams, gypsum stacks and coal ash piles, to subdivisions, parks, and an airport expansion. Autodesk Certified Professional in Civil 3D and an expert in Autodesk infrastructure software. Trainer and consultant with IMAGINiT Technologies.

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