What to do with the ceiling of the slope arc house

The ceiling carpenter can do it, the middle nail is bolted to the line, the other end is tied to the pen, and the straight is drawn along the outer circle! If there is still a slope shape like a bowl inside, the average carpenter really can't do it! Use the wooden board to make a circle of arc modeling, in the gypsum plate spelling, the process is very complicated, all of which can be involved in making villas, and the labor cost is expensive.