Sketcher BSplineInsertKnot

Description
Insert a knot into an existing B-spline (See this page for more info about B-splines). If a knot already exists at the specified parameter, increases the multiplicity of that knot by one.

Usage

 * 1) Select a B-spline, then either:
 * 2) * Press the button.
 * 3) * Use the menu.
 * 4) Move the cursor to the desired location where the new knot point is to be created, and click to insert the knot. The parametric value of the knot is displayed for reference.
 * 5) (Optionally) Repeat the step above to create more knots.
 * 6) Right click or press  to exit knot insertion mode.
 * 7) (Optionally) Use Sketcher_BSplineIncreaseKnotMultiplicity.svg Increase knot multiplicity to increase the multiplicity of the knot(s), if desired.