A Relief scan, also called a bas relief, is like a height map. It consist of a number of points with height associated. Typically points in XY-plane with Z heights.
A cylindrical scan is a 360 degree scan made on a rotary axis, typically a turning lathe. It’s like a Relief scan but just wrapped around a cylinder.
Turning lathe scan
A 3D scan is a number of Relief scan joined into one complete 3D object.
200 mm long statue of a horse with rider
2 meter long statue of a wolf by Claus Ønstoft
Restoration in sandstone