Sketcher CreatePeriodicBSplineByInterpolation: Difference between revisions
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|[[Sketcher_CreateBSplineByInterpolation|B-spline by |
|[[Sketcher_CreateBSplineByInterpolation|B-spline by knots]] |
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|[[Sketcher_CreateRectangle|Rectangle]] |
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|[[Sketcher_CreatePolyline|Polyline]] |
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|[[Sketcher_Workbench|Sketcher]] |
|[[Sketcher_Workbench|Sketcher]] |
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|IconL=Sketcher_CreateBSplineByInterpolation.svg |
|IconL=Sketcher_CreateBSplineByInterpolation.svg |
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|IconR= |
|IconR=Sketcher_CreateRectangle.svg |
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|IconC=Workbench_Sketcher.svg |
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{{GuiCommand |
{{GuiCommand |
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|Name=Sketcher |
|Name=Sketcher CreatePeriodicBSplineByInterpolation |
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|MenuLocation=Sketch → Sketcher geometries → |
|MenuLocation=Sketch → Sketcher geometries → Create periodic B-spline by knots |
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|Workbenches=[[Sketcher_Workbench|Sketcher]] |
|Workbenches=[[Sketcher_Workbench|Sketcher]] |
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|Shortcut={{KEY|G}} {{KEY|B}} {{KEY|O}} |
|Shortcut={{KEY|G}} {{KEY|B}} {{KEY|O}} |
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|Version=0.21 |
|Version=0.21 |
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|SeeAlso=[[ |
|SeeAlso=[[Sketcher_CreateBSplineByInterpolation|Sketcher CreateBSplineByInterpolation]] |
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}} |
}} |
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==Description== |
==Description== <!--T:3--> |
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The [[Image:Sketcher_CreatePeriodicBSplineByInterpolation.svg|24px]] [[Sketcher_CreatePeriodicBSplineByInterpolation|Sketcher CreatePeriodicBSplineByInterpolation]] tool creates a periodic (closed) B-spline curve through knot points. See [[B-Splines|this page]] for more information about B-splines. |
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This tool creates a periodic B-spline curve passing through given points. See [[B-Splines|this page]] for more info about B-splines. |
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See also: [[Sketcher_Workbench#Drawing_aids|Drawing aids]]. |
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# There are several ways to invoke the tool: |
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⚫ | |||
#* Select the {{MenuCommand|Sketcher → Sketcher geometries → [[Image:Sketcher_CreatePeriodicBSplineByInterpolation.svg|16px]] Create periodic B-spline by knots}} option from the menu. |
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#* Use the keyboard shortcut: {{KEY|G}} then {{KEY|B}}, then {{KEY|O}}. |
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# For further steps see [[Sketcher_CreateBSplineByInterpolation#Usage|Sketcher CreateBSplineByInterpolation]]. |
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==Notes== <!--T:7--> |
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See [[Sketcher_CreateBSpline#Notes|Sketcher CreateBSpline]]. |
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# Create a series of points by clicking in the [[3D_view|3D view]]. While the command is active, the created points are connected with straight lines. |
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# Optionally press {{KEY|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). |
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# Optionally press {{KEY|Backspace}} before terminating the input to delete the last created control point. |
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# Right-click to terminate the input and generate the curve. |
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# Depending on preferences, the tool may remain active to trace a new curve. Right-click again to exit the command. |
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* After a B-spline is created, it is possible to define the weight of the control points by changing the radii of the weight circles. The equality constraints on the circles need to be deleted first. The radius constraint is arbitrary, the weight of the control points will be defined by the relative radii of the circles. It works similar to gravity: the bigger a circle is in relation to the others, the more the curve will be attracted to the control point. |
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* The visibility of the control polygon, the curvature comb, the degree and the knot multiplicity can be toggled on/off from the [[Sketcher_Workbench#Sketcher_B-spline_tools|B-spline tools]] toolbar. |
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* Check out the other tools in the [[Sketcher_Workbench#Sketcher_B-spline_tools|B-spline tools]] toolbar for more B-spline editing tools. |
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==Limitations== |
==Limitations== <!--T:9--> |
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* The resultant curve is no different than the curve defined through control points. So all limitations of a periodic B-spline apply. |
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See [[Sketcher_CreateBSplineByInterpolation#Limitations|Sketcher CreateBSplineByInterpolation]]. |
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* The B-splines created are always cubic (i.e. with degree 3). |
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* The defined multiplicity may not always be respected |
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** For a periodic spline, the first knot (coincident with last) always has a multiplicity of 2. |
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** 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. |
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{{Docnav |
{{Docnav |
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|[[Sketcher_CreateBSplineByInterpolation|B-spline by |
|[[Sketcher_CreateBSplineByInterpolation|B-spline by knots]] |
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|[[Sketcher_CreateRectangle|Rectangle]] |
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|[[Sketcher_CreatePolyline|Polyline]] |
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|[[Sketcher_Workbench|Sketcher]] |
|[[Sketcher_Workbench|Sketcher]] |
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|IconL=Sketcher_CreateBSplineByInterpolation.svg |
|IconL=Sketcher_CreateBSplineByInterpolation.svg |
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|IconR= |
|IconR=Sketcher_CreateRectangle.svg |
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|IconC=Workbench_Sketcher.svg |
|IconC=Workbench_Sketcher.svg |
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}} |
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Revision as of 10:50, 23 April 2024
Sketcher CreatePeriodicBSplineByInterpolation |
Menu location |
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Sketch → Sketcher geometries → Create periodic B-spline by knots |
Workbenches |
Sketcher |
Default shortcut |
G B O |
Introduced in version |
0.21 |
See also |
Sketcher CreateBSplineByInterpolation |
Description
The Sketcher CreatePeriodicBSplineByInterpolation tool creates a periodic (closed) B-spline curve through knot points. See this page for more information about B-splines.
Usage
See also: Drawing aids.
- There are several ways to invoke the tool:
- Press the Periodic B-spline by knots button.
- Select the Sketcher → Sketcher geometries → Create periodic B-spline by knots option from the menu.
- Use the keyboard shortcut: G then B, then O.
- For further steps see Sketcher CreateBSplineByInterpolation.
Notes
Limitations
See Sketcher CreateBSplineByInterpolation.
Sketcher
- General: Create sketch, Edit sketch, Map sketch to face, Reorient sketch, Validate sketch, Merge sketches, Mirror sketch, Leave sketch, View sketch, View section, Toggle grid, Toggle snap, Configure rendering order, Stop operation
- Sketcher geometries: Point, Line, Arc, Arc by 3 points, Circle, Circle by 3 points, Ellipse, Ellipse by 3 points, Arc of ellipse, Arc of hyperbola, Arc of parabola, B-spline by control points, Periodic B-spline by control points, B-spline by knots, Periodic B-spline by knots, Polyline, Rectangle, Centered rectangle, Rounded rectangle, Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, Regular polygon, Slot, Fillet, Corner-preserving fillet, Trim, Extend, Split, External geometry, Carbon copy, Toggle construction geometry
- Sketcher constraints:
- Geometric constraints: Coincident, Point on object, Vertical, Horizontal, Parallel, Perpendicular, Tangent, Equal, Symmetric, Block
- Dimensional constraints: Lock, Horizontal distance, Vertical distance, Distance, Radius or weight, Diameter, Auto radius/diameter, Angle, Refraction (Snell's law)
- Constraint tools: Toggle driving/reference constraint, Activate/deactivate constraint
- Sketcher tools: Select unconstrained DoF, Select associated constraints, Select associated geometry, Select redundant constraints, Select conflicting constraints, Show/hide internal geometry, Select origin, Select horizontal axis, Select vertical axis, Symmetry, Clone, Copy, Move, Rectangular array, Remove axes alignment, Delete all geometry, Delete all constraints
- Sketcher B-spline tools: Show/hide B-spline degree, Show/hide B-spline control polygon, Show/hide B-spline curvature comb, Show/hide B-spline knot multiplicity, Show/hide B-spline control point weight, Convert geometry to B-spline, Increase B-spline degree, Decrease B-spline degree, Increase knot multiplicity, Decrease knot multiplicity, Insert knot, Join curves
- Sketcher virtual space: Switch virtual space
- Additional: Sketcher Dialog, Preferences, Sketcher scripting
User documentation
- Getting started
- Installation: Download, Windows, Linux, Mac, Additional components, Docker, AppImage, Ubuntu Snap
- Basics: About FreeCAD, Interface, Mouse navigation, Selection methods, Object name, Preferences, Workbenches, Document structure, Properties, Help FreeCAD, Donate
- Help: Tutorials, Video tutorials
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