Here’s a tip for those of you who hate drawing polyline borders point by point in order to do a take-off, or a hatch. Try REC and REG (rectangle and region).

First, get used to using the often overlooked REC command. It may seem like a simple thing, picking two points to draw a closed orthogonal polyline (big deal, you can do that with ortho and snap), but when combined with the mighty REGION command, you’re cooking with gas. I like REC because you can cover an area with just two clicks instead of four, and let’s face it, most architectural plans are made out of rectangles (corridors, rooms…). Plus, the x,y coordinates come out nice and consistent, from bottom-left to upper-right.

On a new layer (e.g. A-AREA) start drawing rectangles all over the place, overlapping them with abandon. We’ll clean it up in the next step. All you need to do is make sure you’ve covered the entire area you’re interested in, with as many rectangles as you need.

Now, isolate that layer so you don’t mess with your drawing (LAYISO). Type REG and select everything/hit enter. It will look like nothing happened, but really you’ve just turned all those polylines into regions. What’s a region?

Regions are two-dimensional enclosed areas you create from objects that form closed loops. Loops can be combinations of lines, polylines, circles, arcs, ellipses, elliptical arcs, and splines. The objects that make up the loops must either be closed or form closed areas by sharing endpoints with other objects.

The special thing about regions? You can perform 2D Boolean operations on them: union, subtraction and intersection. So now that you have regions, type UNI (for union) and select everything again/hit enter. You’ll see all your rectangles merge into a single shape. Yeah, mind-blowing, isn’t it? It gets better: you can subtract regions from one another. Type SU, select your main region (the one you want to keep), hit enter, then select the region that will be subtracted (the cutting shape)/hit enter. You’ll see that second region cut away from the first. And you can use this method to make donuts. That is, you can cut out islands in the middle of your regions, and Autocad, for once, knows what you’re trying to do. (You can also INTERSECT regions, but I’ve rarely found use for that.)

Now that you have a region, with or without donut holes, you can get properties to find its area, and you can select it as an object to hatch. Autocad’s gotten better at hatching complex polylines with islands, but it’s still not perfect. However, I’ve never had a problem hatching a region. It works every time, no matter how many holes you cut out.

One thing about regions: you’ll see that the vertices are not editable like a polyline. The whole shape moves as a block. No matter, you can always explode regions when you need to. And of course, you can build the pieces back into polylines and regions again, now that the JOIN command is so much better.

You’ll notice that in the above definition of REGION they mention shapes other than rectangles. This is true–you can mix all kinds of things, as long as they’re all in the same plane. Many possibilities. Enjoy.

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