Round service hatches?

[aheidel]

I'm making a model of a raw reinforced concrete house and I'd like to indicate where holes in walls go. Like 100mm holes for bathroom fans, 70mm holes for AC, 150mm holes for clothes dryer, etc. Service hatches are rectangular but I need something circular.

Any ideas?

[hansmex]

Make two thin and low halfround walls, connected at beginning and end.
Export and import, checking door-window so that you can insert it in a wall.

H

[aheidel]

That's brilliant! Worked perfectly (after a few mistakes).

Thank you.

[baldyman]

There's a round window. Just make it invisible.