Spline (Control Points)
Toolbar / Icon:
Menu: Draw > Spline > Spline (Control Points)
Shortcut: S, P
Commands: spline  sp
Description:
Draws spline curves from control points. Nonuniform rational BSplines
(NURBS) with homogeneous weighting factors are the only splines that are
supported.
Procedure:
 Choose the degree of the spline in the options tool bar. Supported
degrees are 2 (quadratic bspline) and 3 (cubic bspline). The higher the
degree, the 'smoother' the curve becomes.
Note that a quadratic bspline requires by definition at least 3
control points while a cubic bspline has at least 4 control points.
 Check the 'Closed' check box in the options tool bar if you want to
create a closed spline. Closed splines are continuous closed loops.
 Specify the control points. After defining the third (for quadratic
bsplines) or fourth (for cubic bsplines) control point, a preview will be
shown. You can remove the last control point again by clicking the 'Undo'
button in the options tool bar.
 Hit escape or click the right mouse button after setting the last point
to confirm the spline shape.
 You can not create another spline or rightclick again to terminate the
tool.
Example for two open splines (quadratic and cubic):
Example for two closed, periodic splines (quadratic and cubic):
