Discover the three types of coordinate entry in AutoCAD that is built on a coordinate system using absolute coordinates. Learn how to use these coordinates effectively while drawing and understand their significance in the overall design process.
Key Insights
- The three types of coordinate entry in AutoCAD are absolute coordinates, relative coordinates, and polar relative coordinates. Absolute coordinates start at 0, 0 and move positively towards the right in the x direction, with positive y towards the top, negative x to the left, and negative y to the bottom.
- Relative coordinates represent changes in the x and y direction. It is used when the exact starting or ending points are not known. The changes are indicated with an '@' symbol followed by the changes in x and y positions.
- Polar relative coordinates represent changes from the last point but in terms of distance and direction. This is usually associated with angles and is used for very precise angles that might not be available in the polar snap options.
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Before we begin drawing our electrical symbols, I would like to talk about the three types of coordinate entry in AutoCAD. Just as a reminder, AutoCAD is built on a coordinate system, and it is built using absolute coordinates.
That starts at 0, 0, and moves positively to the right in the x direction. That's positive x to the right, positive y is to the top of the screen, negative x is to the left, and negative y is to the bottom of the screen. As we mentioned earlier, this is our positive, positive quadrant.
In order to use absolute coordinates when drawing, all we need to do is to type in the values, one after another, separated by commas. For this example, I'm going to use the line tool, and you do not have to follow along with this example, but if you would like to, please open a new file now. This file is not provided to you in the course data sets because it is not a graded element, and it will not be used in any course submissions.
I'm going to go to the line tool, and to begin, I'm going to type 0, 0, and that is because I know exactly where I want to go. Then I'll type 1, 0, which moves us in the positive x direction, 1, to go to 1, 0. Again, this is the absolute location of positive 1 and 0. Then, if I want to go to the absolute location of 1, 1, I can type 1, 1, enter. Then you can see the pattern, 0, 1, which is 0 change in the x, so it's right along the vertical line, and 1 in the y, so it's above 0, 0, enter, and then to finish, I'll go to 0, 0 one more time, enter to say I'm done.
These are the absolute locations of those coordinates. Next, we can look at relative coordinates, and when we talk about relative, we're talking about changes, so it's the change in the x direction and the change in the y direction, and we use relative coordinates when we do not know exactly where we are starting or exactly where we are going. So, in this case, I'm going to go back to the line tool, and I'm going to start by clicking right here.
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Now, I can see that if I want to go to the right, I want to go at, which is shift and 2, you'll see that in my command prompt, I've added the at symbol, and the 1, 0 means at relative 2, I'm changing the position to go positive 1 in the x, and no change in y, so this is a line that's drawn straight to the right. Enter to lock it in. Then, if I want to go up, I go at 0, 1, that's no change in x, and then a positive 1 change in y. At 0, 1. Enter.
Now, to go back to the left, I have to do at negative 1, 0, and the negative, again, means to move left along the negative x direction. At negative 1, 0. From where I started, which is this point here, I'm negatively moving in the x, and no change in y. Enter to lock it in. And to go back to this point, I can go at, no change in x, so 0, comma, a negative 1 change in y. Negative 1. I'm moving down the screen, so that's a negative y value.
Enter to lock it in. Enter to say I'm done. I do not know the absolute coordinates of any of those four points on the screen, but I can say with certainty that that is a perfect square.
I just don't know where the points are relative to 0, comma, 0. The final coordinate entry option is polar relative coordinates. Notice, relative is still in the name, so this means change from your last point, but this is distance and direction. This means what direction am I going, and what is the distance? So it's distance first, and then direction, which has to do with angle.
Now when we see polar, we always should think angles. Polar always works with angles, just like our polar snap. Now sometimes our polar snap does not have the angle we need.
If it's 33 degrees or 22.5 degrees, it might not be automatically on our polar snap options, and it is not worth it to set up every degree or every half degree in your polar snap. It'll just become very annoying. If we need a very precise angle, we can use polar relative coordinates.
In this case, I'll start my line again here, and in this case, you'll notice the distance is always the same. We are always moving a distance of 1. All that changes is our angle. 0 is the angle that is straight to the right.
Then it goes in a counterclockwise rotational direction all the way to 360. 90 is vertical, 180 is to the left, 270 is negative down the screen, and again 0 is the same as 360, and those point to the right. So I'm going to go at 1 angle 0. That means a distance of 1, and an angle or a direction of 0, which is to the right.
Then I can go at 1 angle 90. 90 is a straight up direction. Enter.
At 1 angle 180, 180 degrees. Enter. And then at 1 angle 270, and that is a downwards direction.
Enter. Enter to say that I'm done. Throughout the rest of this course, we will be using absolute coordinates, relative coordinates, and occasionally polar relative coordinates.
See you in the next video.
