Sketcher CreateBSplineByInterpolation

Description
This tool creates a B-spline curve passing through given points. See this page for more info about B-splines.

Usage

 * 1) Press the  button.
 * 2) Create a series of points by clicking in the 3D view. While the command is active, the created points are connected with straight lines.
 * 3) Optionally press  before terminating the input to define the multiplicity of the knot at the last defined point (note that this may not always be respected; see limitations for details).
 * 4) Optionally press  before terminating the input to delete the last created control point.
 * 5) Right-click to terminate the input and generate the curve.
 * 6) Depending on preferences, the tool may remain active to trace a new curve. Right-click again to exit the command.

Limitations

 * The resultant curve is no different than the curve defined through control points. So all limitations of a non-periodic B-spline apply.
 * The B-splines created are always cubic (i.e. with degree 3)
 * The defined multiplicity may not always be respected
 * For a non-periodic spline, the first and last knots always have a multiplicity of 4.
 * If the points just before and just after have multiplicities >=3, the piece between these two is fully continuous, and this (middle) point will only be constrained with point-on-object. If a knot is needed, consider using the insert knot tool.