This is a long shot, but is there an extension that will auto-calculate the area of specified surfaces?
I want a quick way to calculate something like “Area of Surface 1 + Area of Surface 2 - Area of Surface 3”
I am designing a house and I need to stay below a specified number of square meters, and as I change the design I need to keep doing those calculations manually. An automated way of doing this would be very helpful.
If the surfaces are in the same drawing context you can just select them all at once and read the total area in Entity Info.
I also feel like there’s a great need for this, and am surprised it hasn’t been addressed. Selecting multiple surfaces of complex shapes while avoiding edges can be a daunting task.
Within the same context you can just turn off edges to get a face area.
You can select faces of complex objects without the edges with the free plugin selection Toys from ThomThom, you can also select only edges, smooth edges, hidden lines, groups components, guides, guide points, select by material, by area, convert groups and it’s instances into components and some more options, it’s one of my favorite plug-ins. You can also use Box’s method to avoid selecting edges.
There is my extension FredoTools::ReportLabelArea which allows to interactively select faces/surfaces (or group / componets) and give their area. You can also report areas in the model.
You can use my plugin (Atmaca Report Entities ). When you run the plugin, it presents the materials in each group in the form of a group-by-group table. If you want, it also gives the total material area in the drawing.
You can of course colour the surfaces with a unique colour material and use the select by material option to total the area… use this technique all the time when doing urban landuse plans
You don’t even have to do that. You can right-click on the unique material in the In Model section of the Materials browser and select Area from the context menu.
AH yes… that too 
Another way is to click on a face then Shift click on additional faces to add them to the selection.
When done, you can read the total area in Entity Info.
