Ready to watch this entire course?
Become a member and get unlimited access to the entire skills library of over 4,900 courses, including more CAD and personalized recommendations.Start Your Free Trial Now
- View Offline
- 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
Skill Level Beginner
No matter how complicated a drawing looks, it's essentially a collection of straight lines and curves. Well, we've seen how to create straight lines. In this lesson, we'll learn how to draw some curves in the form of circles. Specifically, we'll be looking at the radius and diameter method of creating circles. On my screen, I've got an example of a circle. Let's take a second and talk just a little bit about how circles are measured. A circle's radius is the distance from the center point to the edge of the circle, and a circle's diameter is the distance from one side of the circle to the other, where that measurement passes through point.
It's essentially the width of the circle. To draw a circle, I'll move up to the Draw panel in the Ribbon and click the Circle icon. I will then click to define the center point of my circle. And as I pull away, notice I'm getting the same rubber-band effect that we get when we create a line segment. I'm going to pull out a little bit. I'll click one more time to define the circle's radius. Now this circle is nice, but it has no real geometric value. Let's create another circle, except this time we'll base the circle on a real measurement. I'm going to press my spacebar to relaunch the command. I'll pick to define my center point, and then I'm going to give this circle a radius of three, and I'll press Enter, all right? Let's say I'd like to create another circle with the same radius.
Once again, I'll re-launch the command, I'll pick a point onscreen, and take a look at the command line. Notice this number inside these little carets. This represents the default measurement for the command. You'll see a number like this in several AutoCAD commands. Essentially AutoCAD remembers the previous value that you used the last time you launched that command. So, if I want to create another circle with a radius of 3, all I have to do is press Enter and accept that default value. Let's create another circle, except this time we'll create it using a diameter. I'm going to move up and relaunch the command. I'll pick my center point and then if we look at the command line, notice there's a suboption right here representing diameter.
I'll click to select that, and I'll give this circle a diameter of 2, then I'll press Enter. Now, if you were looking closely, you probably noticed that the Circle icon has a flyout underneath it. If I click this, it will open up my Circle menu, showing me all of the different ways that I can construct a circle. Actually, there is only one circle command, the default being Center Radius. The rest of these are merely shortcuts to the suboptions within that main command. For instance, if I wanted to draw another circle using the diameter method, I can simply choose Center Diameter, pick my center point onscreen, and if you look at the command line you can see the computer's entered the D for diameter for me. Like I said, it's a convenience, a shortcut if you will. Let's create this circle with a diameter of 1.5, and I'll press Enter.
So, be aware that these additional options are here. Use them if you wish. Just note that if you do select one of these shortcuts, that guy will become the default the next time you launch the Circle command from up here. Now that we understand how the circle command works, let's try it out. I'm going to pan the drawing over. On my screen, I have some example circles. Let's see if we can recreate this geometry. I'll start with this circle right here. Since this circle is asking for a radius, I'm going to open the flyout and choose this Center Radius method. I'll click to define my center point, and the circle has a radius of 2.5. Now, press Enter. Next, we'll recreate this one. Take a look at this icon that's being used in the dimension. This is a standard symbol representing diameter.
So, to create this circle, I'll launch the Circle command, pick my center point, I'm going to use the diameter option, and I'll give this a diameter of 2.25. Finally, we'll create this circle. Notice that it's dimension is conspicuously absent. That's all right. We can get the dimension ourselves. If I select this circle and come over to my Properties palette, my palette happens to be anchored to the left side of the screen. If your Properties palette is not visible, you can press Control+1 to toggle its display. I will then come down to the Geometry area, and I can see that this circle has a radius of 4. So, I'll move my cursor back into model space and I'll press Escape to deselect the object. I'll launch the Circle command one more time, pick my center point, and give this circle a radius of four. I'm sure you'll agree that knowing what we know now, it's safe to say that we can create just about any circle that our design may require.