Sketcher CreateBSplineByInterpolation: Difference between revisions

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The [[Image:Sketcher_CreateBSplineByInterpolation.svg|24px]] [[Sketcher_CreateBSplineByInterpolation|Sketcher CreateBSplineByInterpolation]] tool creates a B-spline curve through knot points. See [[B-Splines|this page]] for more information about B-splines.
The [[Image:Sketcher_CreateBSplineByInterpolation.svg|24px]] [[Sketcher_CreateBSplineByInterpolation|Sketcher CreateBSplineByInterpolation]] tool creates a [[B-Splines|B-spline]] curve through knot points. {{Version|1.0}}: This is the same tool as [[Sketcher_CreateBSpline|Sketcher CreateBSpline]] but with a different initial mode.


==Usage== <!--T:5-->
==Usage== <!--T:5-->
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#* Select the {{MenuCommand|Sketcher → Sketcher geometries → [[Image:Sketcher_CreateBSplineByInterpolation.svg|16px]] Create B-spline by knots}} option from the menu.
#* Select the {{MenuCommand|Sketcher → Sketcher geometries → [[Image:Sketcher_CreateBSplineByInterpolation.svg|16px]] Create B-spline by knots}} option from the menu.
#* Use the keyboard shortcut: {{KEY|G}} then {{KEY|B}}, then {{KEY|I}}.
#* Use the keyboard shortcut: {{KEY|G}} then {{KEY|B}}, then {{KEY|I}}.
# For further steps see [[Sketcher_CreateBSpline#Usage|Sketcher CreateBSpline]].
# The cursor changes to a cross with the tool icon.
# Pick several knot points.
# Optionally press {{KEY|M}} before finishing the input to define the multiplicity of the last defined knot point (this may not always be respected, see [[#Limitations|limitations]] for details).
# Optionally press {{KEY|Backspace}} before finishing the input to delete the last knot point.
# Right-click or press {{KEY|Esc}} to finish the input.
# The B-spline is created, including a set of internal geometry (weight circles and knot points).
# If the tool runs in [[Sketcher_Workbench#Continue_modes|continue mode]]:
## Optionally keep creating B-splines.
## To finish, right-click or press {{KEY|Esc}}, or start another geometry or constraint creation tool.


==Notes== <!--T:7-->
==Notes== <!--T:7-->
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==Limitations== <!--T:9-->
==Limitations== <!--T:9-->


See [[Sketcher_CreateBSpline#Limitations|Sketcher CreateBSpline]].
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* The resultant curve is no different from a (non-uniform) B-spline defined through control points. So all related limitations apply. See [[Sketcher_CreateBSpline#Limitations|Sketcher CreateBSpline]].
* The created B-splines 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.





Revision as of 08:27, 27 June 2024

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Sketcher CreateBSplineByInterpolation

Menu location
Sketch → Sketcher geometries → Create B-spline by knots
Workbenches
Sketcher
Default shortcut
G B I
Introduced in version
0.21
See also
Sketcher CreatePeriodicBSplineByInterpolation

Description

The Sketcher CreateBSplineByInterpolation tool creates a B-spline curve through knot points. introduced in version 1.0: This is the same tool as Sketcher CreateBSpline but with a different initial mode.

Usage

See also: Drawing aids.

  1. There are several ways to invoke the tool:
    • Press the B-spline by knots button.
    • Select the Sketcher → Sketcher geometries → Create B-spline by knots option from the menu.
    • Use the keyboard shortcut: G then B, then I.
  2. For further steps see Sketcher CreateBSpline.

Notes

See Sketcher CreateBSpline.

Limitations

See Sketcher CreateBSpline.