A spline is a smooth curve that passes through or near a given set of points. You can control how closely the curve fits the points.
The SPLINE command creates a particular type of spline known as a nonuniform rational B-spline (NURBS) curve. A NURBS curve produces a smooth curve between control points.
You create splines by specifying points. You can close the spline so that the start and endpoints are coincident and tangent.
Tolerance describes how closely the spline fits the set of fit points you specify. The lower the tolerance, the more closely the spline fits the points. At zero tolerance, the spline passes through the points. You can change the spline-fitting tolerance while drawing the spline to see the effect.
You can use two methods for creating splines:
You can easily convert spline-fit polylines into true splines with SPLINE.