You can use any common window on a curved wall. Instead of using wall opening, use an in-place void to create arc opening on a curved wall.
Andrej Ilić
phonetical: ændreɪ ilich
MSc Arch
Autodesk Expert Elite Alumni
Here is a screencast showing the technique dr. grozozo is describing. I just happened to have an old one on hand.
hello @Anonymous
https://knowledge.autodesk.com/community/screencast/b1d211bf-f9ab-4628-ad26-d7f279ee689f