How to make arch entrance in the dome tent?

[Shinehead]

Hello all,

I am trying to make arch entrance in the tent.

What is the best way to make arch shaped cut in the dome?

[TIG]

Make a second 3d solid the shape of the arched-hole - group it so you can position it without 'sticking'.
Place it so that it intersects the main shape as desired.
Edit it and turn the faces inside out [Reverse] so next when we 'intersect' it'll combine correctly.
Now explode the group so it is with the main shape's geometry.
Select the geometry of both and 'Intersect with Selection'.
Cut edges will appear where the two forms intersect with each other.
Next erase the unwanted bits and you have the arched-hole left...

[Shinehead]

Great! Thank you