Using relative coordinates

To explain the relative coordinate system, I will once again use the same diagram that we used in the previous section, but in this case, the line will not start from the origin. Rather, we will start it randomly from any point in the drawing area, as in the following diagram:

So, the same line with a length of 6 units that is not starting from the origin and has an inclined angle of 36 degrees can be made using the following workflow:

1. Type L and press Enter to start the line command.
2. Click on any point in the drawing area to start the line.
3. Type @6<36 in the command line and press Enter.
4. The line with a length of 6 units and a 36 degree angle with respect to the X axis will be made.

This @ sign represents the relative coordinate system, which allowed us to make a line from a point that is not on the origin. Here is another example of relative coordinates.

As explained in the previous example, relative coordinates are helpful when you are making a drawing from a point that isn't the absolute origin and still want to use the selected point as a reference for adding the coordinates. In this example, I will create the following triangle using relative coordinates:

Here, you can start the drawing at point A, which is not on the origin, and then progressively make your drawing by entering distances. Instead of direct distances, however, we will use relative coordinates to make this triangle in the following example:

1. Start by selecting the Line command and then click on a point in the drawing area, making sure that the point is not at the origin. Let’s call it point A. As the A point is chosen randomly, we can’t specify an exact value of the (X,Y) coordinate for the B point with respect to the A point. So, in this case, we can use relative coordinates to specify a coordinate value of the B point with respect to the A point. Relative coordinates assume that the last point you clicked or selected is the origin and then make all measurements from that last point as if that point were the origin.
2. So, if point A were the origin, then point B should be 8,0, with respect to point A. To make the AB horizontal line, type @8,0 and press Enter. The line will end up at point B, as in figure 2.10. Note the @ sign before the coordinate value. This @ sign is added to indicate that the next coordinates are "relative" with respect to the point that we previously clicked, which is the A point, in this case, and it will assume the A point as the origin instead of the absolute origin of the drawing.
3. Once you have reached point B, don’t exit the line command, but type @0,6 and press Enter. You will notice that AutoCAD will reach point C, as in figure 2.10, and in this case, the B point will also be treated as the origin and the coordinate value of the C point with respect to the B point is 0,6, which is shown with the @ sign.
4. You can complete the triangle by clicking again on the A point and then pressing Enter to exit the line command.

So, now that we have seen different methods of making the drawing in AutoCAD, let’s use a combination of these methods to make a simple drawing.