พรุ่งนี้ฉันต้องตื่นแต่เช้าAs they are neither perpendicular nor horizontal, vaults such as arches
and domes obviously demanded a more complex system of measurement.
The master builders of the Gothic cathedrals regulated the curvature of
such structures by first plotting them full-scale, like a giant set of
blueprints, on to special tracing-floors. These floors were covered in
plaster of Paris on to which life-sized geometrical designs of, say, a vault's
ribs would be drawn. Once these drawings were complete, carpenters used
them to devise the wooden templates from which the stone for the ribs
was shaped by the masons working at the quarry. The gypsum floor was
afterwards wiped clear and the next set of drawings incised into its surface.
If facilities for tracing-floors did not exist, an area of ground would be