Menu
: CURVE : Design:Surf SpiralShortcut
: NoneThis command creates a 3D spiral curve which wraps around another surface which should be the target object. A parameter box appears requesting how many loops the spiral should contain and the tolerance. The smaller the tolerance the closer the curve will match the surface but it will be defined using more points.
The result is a 3D Bézier curve contained within a 3D projection set in the current element. This curve set could then be cut and pasted to a new object and used as the basis for further design work such as 3D building.