In this post, I’ll continue my review of the AutoCAD alphabet with the AREA command. You can launch the AREA command using the AA command alias or from various locations in the AutoCAD user interface, including the Inquiry panel of the Tools ribbon panel.
The AREA command enables you to find the enclosed area by picking boundary points or selecting closed objects. For example, to find the area of the stairwell in the following image, launch the AREA command and then pick the 4 corners defined by the magenta segments. If the magenta segments are defined by a single polyline, you can save picks by using the Object option and selecting the polyline.
The default behavior of the AREA command enables you to continue picking points to define a single area. In the following image, for example, you could start with point 1 and continue picking points all the way around the floor plan to point 40 to determine the area. I said you *could*, I didn’t say you should! I’ll use this example to explain the Add and Subtract options as well as to point out a few tips and inaccuracies.
When you begin picking points, pay attention to your first pick because in AutoCAD 2009 and earlier (unless you have the AutoCAD 2009 Subscription Bonus Pack 1), there are no visual indicators to remind you of where you started. Also, it’s up to you to determine how accurate you need to be. In this example, notice the jog in the wall between points 2 and 3 as well as 6 and 7. You could account for these jogs with additional picks or decide the difference is insignificant (as I did in this example) and save a few picks. Also notice the curve between points 7 and 8. When picking points with the AREA command, AutoCAD assumes linear segments. So, in this example, it will calculate the area as if there were a straight line between points 7 and 8.
The AREA command includes two other options (in addition to the Object) option. The Add option enables you to determine the cumulative value of multiple areas by picking multiple closed objects, multiple sets of points, or a combination of both. The Subtract option behaves the same way but it sums the area as a negative value. You can switch between the Add and Subtract options as you continue to select objects or pick sets of boundary points.
The AREA command works great for selecting objects or picking a few boundary points. But, as you can see from this example, picking many boundary points can be time-consuming and prone to error. Curved areas provide an additional challenge.
In my next post, I’ll show you how you can simplify the process of determining the area by first using the BOUNDARY command.