This is a rough model in 4 parts of the cupola on top of St.Thomas Church, Lymington.
The parts, from bottom to top are: White base, Grey base, Arches, Roof.
I've included all the FreeCAD files in case you want to play with it.
Printer:
CTC Replicator Dual
Rafts:
No
Supports:
No
Resolution:
0.25w x 0.25h
Infill:
10%
Notes:
Print the arches upside down.
Clean and glue
The cupola roof shape
This was the fun bit and uses the 'loft' feature of FreeCAD. In the end it was fairly straightforward.