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. |
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. |
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==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. |
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#* Use the keyboard shortcut: {{KEY|G}} then {{KEY|B}}, then {{KEY|I}}. |
#* Use the keyboard shortcut: {{KEY|G}} then {{KEY|B}}, then {{KEY|I}}. |
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# For further steps see [[Sketcher_CreateBSpline#Usage|Sketcher CreateBSpline]]. |
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# The cursor changes to a cross with the tool icon. |
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# Pick several knot points. |
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# 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). |
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# Optionally press {{KEY|Backspace}} before finishing the input to delete the last knot point. |
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# Right-click or press {{KEY|Esc}} to finish the input. |
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# The B-spline is created, including a set of internal geometry (weight circles and knot points). |
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# If the tool runs in [[Sketcher_Workbench#Continue_modes|continue mode]]: |
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## Optionally keep creating B-splines. |
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## To finish, right-click or press {{KEY|Esc}}, or start another geometry or constraint creation tool. |
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==Notes== <!--T:7--> |
==Notes== <!--T:7--> |
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==Limitations== <!--T:9--> |
==Limitations== <!--T:9--> |
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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]]. |
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* The created B-splines 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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** For a non-periodic spline, the first and last knots always have a multiplicity of 4. |
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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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Revision as of 08:27, 27 June 2024
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Menu location |
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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.
- 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.
- Press the
- For further steps see Sketcher CreateBSpline.
Notes
Limitations
- General: Create sketch, Edit sketch, Attach sketch, 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, Polyline, Line, Arc, Arc by 3 points, Arc of ellipse, Arc of hyperbola, Arc of parabola, Circle, Circle by 3 points, Ellipse, Ellipse by 3 points, Rectangle, Centered rectangle, Rounded rectangle, Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, Regular polygon, Slot, Arc slot, B-spline by control points, Periodic B-spline by control points, B-spline by knots, Periodic B-spline by knots, Toggle construction geometry
- Sketcher constraints:
- Dimensional constraints: Dimension, Horizontal distance, Vertical distance, Distance, Auto radius/diameter, Radius, Diameter, Angle, Lock
- Geometric constraints: Coincident (unified), Coincident, Point on object, Horizontal/vertical, Horizontal, Vertical, Parallel, Perpendicular, Tangent or collinear, Equal, Symmetric, Block
- Other constraints: Refraction (Snell's law)
- Constraint tools: Toggle driving/reference constraint, Activate/deactivate constraint
- Sketcher tools: Fillet, Chamfer, Trim, Split, Extend, External geometry, Carbon copy, Select origin, Select horizontal axis, Select vertical axis, Array transform, Polar transform, Scale transform, Offset geometry, Symmetry, Remove axes alignment, Delete all geometry, Delete all constraints
- Sketcher B-spline tools: Convert geometry to B-spline, Increase B-spline degree, Decrease B-spline degree, Increase knot multiplicity, Decrease knot multiplicity, Insert knot, Join curves
- Sketcher visual: Select unconstrained DoF, Select associated constraints, Select associated geometry, Select redundant constraints, Select conflicting constraints, Show/hide circular helper for arcs, 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, Show/hide internal geometry, Switch virtual space
- Additional: Sketcher Dialog, Preferences, Sketcher scripting
![](/images/thumb/9/94/User_hub.png/24px-User_hub.png)
- 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
- Workbenches: Std Base, Assembly, BIM, CAM, Draft, FEM, Inspection, Material, Mesh, OpenSCAD, Part, PartDesign, Points, Reverse Engineering, Robot, Sketcher, Spreadsheet, Surface, TechDraw, Test Framework
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