Methods of polylining and Boundary/BPOLY

So, as a Facilities person using AutoCAD (although Revit can sometimes be finicky about 'bounding' properties and having to manually add/adjust bounding lines, too), polylining is a must for all of us.

I still occasionally run across users who are not familiar with the Boundary command (or BPoly).

I use this command to create polylines from enclosed areas, but, you can also create Regions with it. 

Obviously, in this process, you have to be aware of the polylining standards being used. Whether it is BOMA or some client-specific method. 

If you're plining an area with a predictable pattern (such as a cube farm), setting up construction lines (CONSTRUCTION LINE or RAY) at the midpoint of the walls can be a way to provide yourself with enclosed areas to use the Boundary (BOUNDARY or BPOLY) command on. 
Make sure you have a distinct layer set as Current, so that you can isolate it (LAYISO). 

Annoyingly, in Autocad 2021, it appears that the default LAYISO behavior is to lock layers, rather than the prior default of turning them off, so you'll have to LAYISO > S to change the settings to O. 

If they are the same size, I tend to just draw a rectangle and copy or array as appropriate.

If you have less regular areas, such as an office suite or cafeteria, you will most likely  manually polyline the smaller spaces, then use Boundary on the remaining open space (lobby or seating). 

Just remember handy tools like the M2P OSNAP, where you can click two points and your pline will snap to the midpoint between them, so you can use RECTANG instead of PL to make your bounding lines, where appropriate. 

I actually set up an M2P shortcut on my tool palette, just so I can keep clicking along. 

When working in a busy drawing, I tend to keep my running osnaps to a minimum so I don't snap to the wrong thing, and just select more specific snaps from my TP when they are required. 

So, once you have your surrounding spaces polylined to make an enclosed space, then you can use BPOLY. 

Here the cyan line is my exterior gross, the magenta represents the interior gross line, the blue is for the room boundaries and the yellow is a pair of break lines that prevents islands (Tririga would show an island space as a Child space, but, I believe ARCHIBUS and FM:Systems would freak out about it, islands are a no-no. And, though I am currently a Tririga user, we still avoid islands and do not utilize child spaces with our client.). I feel pretty safe with with an 1/8" gap (.1 if you want to save on the keyboard input). 

A tip for generating the exterior gross line is by using the AREA command. 

My next step would be to select the interior gross line, a room boundary and one of the yellow breaklines and type LAYISO, so all of the other layers are turned OFF. Run the boundary command, select a point inside of the area, and your polyline is generated. 

Confused about the difference between freezing a layer and turning it off?
http://mistressofthedorkness.blogspot.com/2019/09/turning-off-or-freezing-layer-in.html

Now, I did have a reader tell me awhile back that he created a VBA program that would isolate to the desired layers and start the boundary command. I have done a bit of VBA in the past and even had the honor of assisting Lee Ambrosius in his programming labs at AU for years, but, I haven't quite gotten around to making my own program. 
But, even if you're not comfortable with programming, you could also speed things up by isolating these layers and use the Layer States dropdown on the expanded Layers panel on the home tab of the ribbon to create a new layer state and while in the Layer States Manager, Export that setting to import into other drawings. 
Because, of course, if you're using CAFM/IWMS, you are using the exact same layer names every time.

Happy Polylining, folks!