Sketcher CreateBSplineByInterpolation

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Revision as of 10:44, 3 June 2023 by Roy 043 (talk | contribs) ("pick the first curve point" will terminate the curve input.)
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Sketcher CreateBSplineByInterpolation

Menu location
Sketch → Sketcher geometries → Interpolate B-spline
Workbenches
Sketcher
Default shortcut
G B I
Introduced in version
0.21
See also
Sketcher periodic B-spline

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 B-spline by knots 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 M 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 Backspace before terminating the input to delete the last created control point.
  5. Right-click, or pick the first curve point, 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.

Notes

See Sketcher CreateBSpline.

Limitations

  • The resultant curve is no different than a curve defined through control points. So all related limitations apply. See Sketcher CreateBSpline.
  • The B-splines created are always cubic (i.e. with degree 3).
  • The defined multiplicity may not always be respected:
    • For a periodic spline, the first knot (coincident with last) always has a multiplicity of 2.
    • 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.