I am currently working on personal project. I am trying my hand at modular design, but was wondering how would I go about modeling a collapsed dome roof. I dont want the whole thing collapsed but instead have a big gaping hole in the roof. Any tips would be helpful.

Probably cut a hemisphere into 4 pieces, making 2 modules. One piece that tiles around 3 times and one unique piece that contains the damage.

It should be fairly easy if you leave the objects pivot in the center, when you import your slice all you would have to do is copy and rotate it.

I would start with a sphere, which will put the objects pivot in a really good spot for this, right in the center.
Give it an even number of segments like 16 or 32.
Delete the bottom half and all but a quarter slice of the top.
Apply a Normal modifier to flip the polys inside out, assuming its the dome of a ceiling?
Apply edit poly.
Maybe apply Shell, to give the dome some thickness?
Apply symmetry uncheck weld seam this will give you half of a dome.
Apply symmetry uncheck weld seam, click the symmetry modifier so its selected and rotate the gizmo in the viewport 90 degrees (turning on angle snap really helps with this or use the type in coordinate system).
Go back down to edit poly and create your details do your unwrapping on the original piece and those changes will be copied around to the other pieces as you work.
When you're done with the undamaged dome, make one of the pieces unique, do your damage and export your two pieces.
Since they share a common pivot point and its the dead center it will be easy to copy and rotate the pieces.

So your modifier stack will look like this:
Symmetry Rotate 90
Symmetry
Edit Poly (you can apply modifiers ontop of edit poly but under symmetry, and use collapse to)
Shell
Normal
Sphere

If you're using Maya some of these features might not exists and the history stack isn't quite as flexible as the modifier stack is in max so you will be hobbled a bit.

Originally Posted by Vig

Apply symmetry uncheck weld seam, click the symmetry modifier so its selected and rotate the gizmo in the viewport 90 degrees (turning on angle snap really helps with this or use the type in coordinate system).

Why rotate the Symmetry Modifier instead of setting it to 'Y'?

Because people overlook that you can rotate a symmetry modifier and I thought it was worth mentioning. Also if your working smaller than 1/4th you'll need to rotate it, not really sure how small or big he wants to make his modules, I picked 1/4ths because it was easier for me to write up, ha.

its going to be pretty big mabey the total diameter of the dome is like 2240 unreal units wide, but its also going to where the player can view it outside and on the inside of the building so I dont think flipping the normals would work this time, but I totally see why you would do that in any other case.

actually nvm i misread what vig posted