Contours are intersections of a solid or surface with a plane passing through the line specified with the Create Contours tool. This tool creates contours at specified intervals, which can then be used to create a loft surface in order to re-create a solid shape.
To create contours:
Click the Create Contours tool from the 3D Modeling tool set, and then select Preferences from the Tool bar to specify the contour interval.
To create a single contour, specify a Contour Increment of zero.
Click OK.
Click and drag to indicate the position of the intersecting plane.
The contours, a group of NURBS curves, are created.
