Start your free trial now, and begin learning software, business and creative skills—anytime, anywhere—with video instruction from recognized industry experts.

Start Your Free Trial Now

Understanding the Cartesian coordinate system


From:

AutoCAD 2013 Essentials: 02 Drawing Fundamentals

with Jeff Bartels

Video: Understanding the Cartesian coordinate system

AutoCAD is a vector-based application. This means that all of the geometry that we see in a drawing is tied to an underlying coordinate system. This coordinate system allows AutoCAD to know with a high degree of precision where everything spatially exists in a file. In this lesson, we're going to take a behind-the-scenes look at model space to better understand how AutoCAD manages our geometry. Generally speaking, model space represents an infinitely large grid, much like a sheet of graph paper. We draw our geometry on this grid and AutoCAD uses the grid to maintain the accuracy of the file. It does this through the use of baselines. The first is an East-West baseline called the x axis.
please wait ...
Watch the Online Video Course AutoCAD 2013 Essentials: 02 Drawing Fundamentals
1h 56m Beginner May 21, 2012

Viewers: in countries Watching now:

AutoCAD Essentials is a multi-part series that takes a more modular approach to this massive program, used for everything from 2D and 3D CAD design, drafting, and modeling to architectural drawing and engineering projects. In this installment, author Jeff Bartels concentrates on the particulars of creating basic geometry in AutoCAD, including assigning imperial or metric units of measurement, using object snaps to control accuracy, and drawing and transforming basic lines and shapes. The last chapter in the course tests your newfound skills in a short project.

Topics include:
  • Constructing lines
  • Defining a unit of measure
  • Locking to geometry with object snaps
  • Drawing rectangles, circles, and polygons
  • Applying hatch patterns
  • Moving, copying, and rotating objects
  • Erasing elements
  • Undoing and redoing actions
Subject:
CAD
Software:
AutoCAD
Author:
Jeff Bartels

Understanding the Cartesian coordinate system

AutoCAD is a vector-based application. This means that all of the geometry that we see in a drawing is tied to an underlying coordinate system. This coordinate system allows AutoCAD to know with a high degree of precision where everything spatially exists in a file. In this lesson, we're going to take a behind-the-scenes look at model space to better understand how AutoCAD manages our geometry. Generally speaking, model space represents an infinitely large grid, much like a sheet of graph paper. We draw our geometry on this grid and AutoCAD uses the grid to maintain the accuracy of the file. It does this through the use of baselines. The first is an East-West baseline called the x axis.

The x axis is also a number line. Everything to the right of zero is considered positive X. Everything to the left of zero is considered negative x. There is a second baseline that runs North-South. It's called the y axis, and it also represents a number line. Everything above the x axis is considered positive y. Everything below the x axis is considered negative y. AutoCAD uses these intersecting baselines to identify all points on the grid.

It does this through the use of coordinates, and AutoCAD references coordinates using the format x, y. The first coordinate we're going to talk about is the location where the x and y axis intersect. This point has a coordinate value of 0,0. This location is also considered the origin; all other coordinates are measured from this point. For instance, if I pick a point over here, this location would have a coordinate value of 6,2. It's six units in the x direction and two units in the y direction. Let's try another. This point would have a coordinate value of -4,5.

It's negative four units in the x direction and five units in y. Remember, the format is always x, y. We'll do one more. How about this one? This point has a coordinate value of 9,-3. Nine units in the x, negative three units in the y. Knowing this, when I create a line onscreen, AutoCAD views this object as an entity that was drawn from coordinate -8,-3 to a coordinate of -9,7. Having these coordinates, AutoCAD can easily calculate the length of the line and the direction in which it was drawn. AutoCAD views all geometry within the context of coordinates. Let's return to model space.

As you can see, I'm sitting in the default template file. I'm going to zoom out slightly, and I'll pan the drawing up a little bit. Notice the grid that we see onscreen. This is a visual reminder of the underlying coordinate system. In fact, you can easily identify the location of the baselines. The x axis appears red and the y axis appears green. Take a look at this icon. This is called the UCS icon. UCS stands for User Coordinate System, and this icon identifies the direction of positive x and positive y. Notice down here in the lower-left corner of the screen. As I move my cursor, you can see it's coordinate location updating in real time. So, everything we create is based on an underlying coordinate system.

At this point, you may be wondering if it's possible to create geometry using coordinates. The answer is yes you can, although we don't do it very often. Let's try it. Since we're going to be drafting using coordinates, I'm going to make one quick change. I'm going to come down and turn off the Dynamic Input. Dynamic Input tends to take some liberties with our coordinates, and I don't want to get into that right now so we'll toggle that off momentarily. I'm going to create a circle first. I'll launch the command and rather than picking my center point onscreen, I'm going to enter the coordinate value 10,5, and I'll press Enter. I will then create the circle with a radius of 3. Then I'll press Enter. Now, let's say I'd like to create another circle, twenty units to the right of this one. Well, using coordinates, that's very easy. I'm going to press the spacebar to relaunch the Circle command, and this circle's center point would have a coordinate value of 30,5.

I'll press Enter, and then I'll press Enter again to create a circle the same size as the last one. Let's do one more thing. Maybe I'd like to draw a line from the center of this circle to the center of this one. Once again, this is very easy because I know those coordinates. I'm going to move up and launch the Line command. I will start my line at the coordinate 10,5. I'll press Enter, and I'll draw this to coordinate 30,5. Enter. When I'm finished, I'll press the Escape key.

As you can see, since this drawing is based on an underlying coordinate system, AutoCAD can easily maintain the accuracy of the line work. And it allows us to create new geometry with a high degree of precision.

There are currently no FAQs about AutoCAD 2013 Essentials: 02 Drawing Fundamentals.

 
Share a link to this course

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

* Estimated file size

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

Upgrade to View Courses Offline

login

With our new Desktop App, Annual Premium Members can download courses for Internet-free viewing.

Upgrade Now

After upgrading, download Desktop App Here.

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 ?

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:

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.

Learn more, save more. Upgrade today!

Get our Annual Premium Membership at our best savings yet.

Upgrade to our Annual Premium Membership today and get even more value from your lynda.com subscription:

“In a way, I feel like you are rooting for me. Like you are really invested in my experience, and want me to get as much out of these courses as possible this is the best place to start on your journey to learning new material.”— Nadine H.

Start your FREE 10-day trial

Begin learning software, business, and creative skills—anytime,
anywhere—with video instruction from recognized industry experts.
lynda.com provides
Unlimited access to over 4,000 courses—more than 100,000 video tutorials
Expert-led instruction
On-the-go learning. Watch from your computer, tablet, or mobile device. Switch back and forth as you choose.
Start Your FREE Trial Now
 

A trusted source for knowledge.

 

We provide training to more than 4 million people, and our members tell us that lynda.com helps them stay ahead of software updates, pick up brand-new skills, switch careers, land promotions, and explore new hobbies. What can we help you do?

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:

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:

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.