Sketcher CreatePeriodicBSpline
Jump to navigation
Jump to search
Menu location |
---|
Sketch → Sketcher geometries → Create periodic B-spline |
Workbenches |
Sketcher |
Default shortcut |
None |
Introduced in version |
0.17 |
See also |
Sketcher B-spline |
Contents |
Description
This tool traces a periodic (closed) B-spline curve from its control points.
A periodic B-spline curve (in white) made from 5 points. Pictured are the control polygon in green (the straight lines connecting the red points), the weight circles in blue and the curvature comb in green. The (3) digit in the centre refers to the degree of the B-spline, and the (1) and (2) digits on the knots lying on the curve refer to their multiplicity.
Usage
- Press the Periodic B-spline button.
- Create a series of points by clicking in the 3D view. While the command is active, the created points are connected with straight lines, and a construction circle is created centred on each point.
- Pick the first curve point, or right-click to terminate the input and generate the curve.
- Depending on preferences, the tool may remain active to trace a new curve. Right-click again to exit the command.
- 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.
- The visibility of the control polygon, the curvature comb, the degree and the knot multiplicity can be toggled on/off from the B-spline tools toolbar.
- Check out the other tools in the B-spline tools toolbar for more B-spline editing tools.
Limitations
- Many types of constraints are not supported at this time. Only the B-spline's control points and knots can be constrained.
- Trimming and extend tools are not supported.
- The shape of a B-spline curve can only be edited by dragging one of the control points. The knots lying on the curve cannot be selected.
Sketcher
- The tools: New sketch, Edit sketch, Leave sketch, View sketch, View section, Map sketch to face, Reorient sketch, Validate sketch, Merge sketches, Mirror sketch
- Sketcher geometries: Point, Line by 2 point, Create an arc, Arc, Arc by 3 Point, Create a circle, Circle, Circle by 3 Point, Create a conic, Ellipse by center, Ellipse by 3 points, Arc of ellipse, Arc of hyperbola, Arc of parabola, Create a B-spline, Create B-spline, Create periodic B-pline, Polyline (multiple-point line), Rectangle, Create regular polygon, Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, Create Regular Polygon, Slot, Fillet, Trimming, Extend, External Geometry, CarbonCopy, Construction Mode
- Sketcher constraints
- Geometric constraints Coincident, Point On Object, Vertical, Horizontal, Parallel, Perpendicular, Tangent, Equal Length, Symmetric, Constrain Block
- Dimensional constraints Lock, Horizontal Distance, Vertical Distance, Distance, Radius, Internal Angle, Snell's Law, Internal Alignment, Toggle reference/driving constraint,
- Sketcher tools Select solver DOFs, Close Shape, Connect Edges, Select Constraints, Select Origin, Select Vertical Axis, Select Horizontal Axis, Select Redundant Constraints, Select Conflicting Constraints, Select Elements Associated with constraints, Show/Hide internal geometry, Symmetry, Clone, Copy, Move, Rectangular Array, 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, Convert Geometry to B-spline, Increase degree, Increase knot multiplicity, Decrease knot multiplicity
- Sketcher virtual space Switch Virtual Space
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
- Workbenches: Std Base; Arch, Draft, FEM, Image, Inspection, Mesh, OpenSCAD, Part, PartDesign, Path, Points, Raytracing, Reverse Engineering, Sketcher, Spreadsheet, Start, Surface, TechDraw, Test Framework, Web
- Deprecated or unmaintained workbenches: Complete, Drawing, Robot
- Hubs: User hub, Power users hub, Developer hub