THANK YOU, @Bubblobill!

That's perfect! Even better since it's resizeable - I can now finally decide what size screen my room will actually need after we finish the remodel. This will go a long way to convincing my wife.

For posterity, here's a good home theater calculator that allows you to ...

I did find that one, but looks like it's two pieces as one object and apparently I'll need to install a converter first before I can import it.

If there's no suitable model, is it possible somehow to just do a rectangular box from the ceiling? How? I thought of putting a thin wall in, but it would ...

I'm looking for a ceiling-mounted electric or pull-down home theater projection screen model.

I haven't found anything suitable in the search interface here or on a generic sweethome3d google search.

If there's no suitable model, is it possible somehow to just do a rectangular box from the ceiling ...