Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Trimming and extending geometry

From: AutoCAD 2013 Essentials: 02 Drawing Fundamentals

Video: Trimming and extending geometry

Making a change to one object can often require the modification of other geometry in a drawing. Fortunately, AutoCAD has some tools to help us clean up line work after making changes. In this lesson, we'll look at the Trim and Extend commands. On my screen, I have a simple drawing. Let's make a change. I'm going to select this circle, and I'll come over to the Properties palette and I'll change its radius from 1.5 to 2.5. When I'm finished, I'll press Escape. Now, I've got a problem. These lines that used to meet the edge of the circle now cross over. I'd like to trim these back to meet the new circle edge.

Trimming and extending geometry

Making a change to one object can often require the modification of other geometry in a drawing. Fortunately, AutoCAD has some tools to help us clean up line work after making changes. In this lesson, we'll look at the Trim and Extend commands. On my screen, I have a simple drawing. Let's make a change. I'm going to select this circle, and I'll come over to the Properties palette and I'll change its radius from 1.5 to 2.5. When I'm finished, I'll press Escape. Now, I've got a problem. These lines that used to meet the edge of the circle now cross over. I'd like to trim these back to meet the new circle edge.

To do this, I'll use the Trim command. Trim can be found in the Modify panel--the icon's right here. After launching the command, I will select my cutting object, or objects, and press Enter, I can then select the objects I'd like to trim. And notice how they get pulled back to meet that cutting object. When I'm finished, I'll press Enter. So when using Trim, we use one object to cut another. Let's work in the other direction. I'm going to select this circle again. I'll come over to Properties, and I'm going to change its radius back to 1.5. Now I've got the exact opposite problem. I need to project these lines out to meet the new circle edge. We'll do this using the Extend command. Extend can also be found in the Modified panel. In fact, it shares the same menu as Trim. I'll launch Extend and I will then select my Boundary Edge and press Enter. Then I will select each object I would like to extend to meet that boundary.

When I'm finished, I'll press Enter. As you can see, the workflow behind Trim and Extend is identical. In fact, these commands are so similar that if you launch one of them, you can access the other by simply holding down the Shift key. Let's take a look. I'm going to zoom out, and I'll pan the drawing over. I'd like to convert this geometry into the shape of a ladder. To do that, I will obviously have to trim off some of the line work and extend some of the others. I'm going to start using the Trim command. I'll create a crossing window to select these vertical lines--these will represent my cutting edges-- and I'll press Enter.

I can then select each of the objects I'd like to trim. Now, I could do that one at a time, or I could use a crossing window to select those objects. Once I'm finished trimming, this is where we would typically launch the Extend command. Take a look at the cursor though. It says, "Select object to trim or shift-select to extend." If I'm in the Trim command and hold down my Shift key, Trim converts to Extend and my cutting edges become boundary edges. When I'm finished, I'll press Enter. Now that we understand the basic workflow behind Trim and Extend, let's try and use these commands in a practical example.

I'm going to zoom out, I'll pan the drawing over again. On my screen, I have a double window with an arched top. Let's say that I'd like to convert this geometry into a single window with more of a Gothic top. I'll start by deleting the geometry that I don't need. I'm going to click in this right- side window, and I'll create a crossing selection, to select these dividers. I'll press Delete to remove them. I will then select the top inside edge and the bottom inside edge.

I will also select this geometry on the right side and press Delete, I'll zoom in a little. Now, I'd like to extend this outside edge up and down to meet the top and bottom edge of the window. I'll launch the Extend command to do that. I'll select the top and bottom edge of the window as my boundary edges and press Enter. I will then click either end of this line to project the geometry out to meet those edges. When I'm finished, I'll press Enter. Now I can use my revised line work to trim off the top and bottom edge.

Let's launch the Trim command. I'll select the right side of the window and press Enter. I will use this right side to trim off the top and the bottom. Let's pan the drawing down. And it doesn't look like I'm going to need these radial dividers any more, so I'll use a crossing window to select these, and I'll press Delete. It looks like the top left side of my Gothic window is in good shape. I would like to copy this geometry on the right over to create the top right side of the window. So, I'll launch the Copy command. I'll use a crossing window to select the geometry and press Enter.

I'll pick it up from the endpoint of the large arc, and I'll place it to the upper-right corner of the window. When I'm finished, I'll press Enter. Finally, I have to do a lot of trimming. I'll move up and launch the Trim command. And rather than going in and trying to pick each individual cutting edge that I need, take a look at the cursor. AutoCAD's saying, "Select cutting objects or

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ.

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Join now "Already a member? Log in

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed AutoCAD 2013 Essentials: 02 Drawing Fundamentals.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferencesfrom the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Are you sure you want to delete this note?

No

Your file was successfully uploaded.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

  • new course releases
  • newsletter
  • general communications
  • special notices

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

  • new course releases
  • newsletter
  • general communications
  • special notices

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.