B-Spline

An open B-Spline does not go through its control points

A clamped B-Spline which at least goes through its first and last control point

B-Spline is short for "basis spline".

Characteristics

they do not go through their control points
they have C2 continuity!
they are a special case of NURBS
in order to have a sharp corner in a B-Spline it takes three control-points at the same position
it is hard to insert a control point without changing the curve
it is hard to make a straight line
depending on its degree, changing one point changes large parts of the curve
they cannot exactly describe circles and ellipses.

In order to make it more intuitive to handle a B-Spline can also be constructed in a way it at least goes through its first and last control point.

B-Spline (Value)
B-Spline (2d)
B-Spline (3d)
B-Spline (3d Wryly)

See also: