I’m trying to design a roof for an API 650 tank. The roof will have several triangular parts which will be welded together. I tried creating with a normal sketch, but I because there is curvature on the outside (to match the cylinder) and a small curvature so that it resembles a cone I haven’t been able to design this part. I read about doing this with metal sheets. But I have only being able to create the roof cone as one part. How can I create the roof with several parts? I like the idea of using metal sheets because I don’t need to specify every dimension, and this would be very useful when they manufacture the parts because I can flatten the sheet. All the triangular parts will have the same dimensions except for the last one, because it will be of smaller size. Thanks in advance.