|Drafting → Bézier tools → Bézier curve|
|Introduced in version|
|Draft CubicBezCurve, Draft BSpline|
The command creates a single Bézier curve of degree
number_of_points - 1. It can be transformed to a piecewise Bézier curve, made up of curves of a specified degree, by changing its properties.
The Draft BezCurve and the Draft CubicBezCurve commands use control points to define the position and curvature of the spline. The Draft BSpline command, on the other hand, specifies the exact points through which the curve will pass.
Bézier curve defined by multiple control points
- There are several ways to invoke the command:
- Click the first point in the 3D view, or type coordinates and press the button in the related Line task panel.
- Click additional points in the 3D view, or type coordinates and press the button in the related Line task panel.
- Press or the button in the related Line task panel, or double-click the last point to finish the command.
- Press or the button to finish the curve, leaving it open.
- Press or the button to close the curve, that is, a segment will be added from the last point to the first one to form a face. At least four points, a curve of degree three, are required to form a face.
- Press or the button to remove the curve segments already placed, but keep editing the curve from the last point.
- Press or the button to adjust the current working plane in the orientation of the last point.
- Press , or after a point to constrain the next point on the given axis.
- To enter coordinates manually, simply enter the numbers, then press between each X, Y and Z component.
- Press or click the checkbox to toggle relative mode. If relative mode is on, the coordinates of the next point are relative to the last one; if not, they are absolute, taken from the origin (0,0,0).
- Press or click the checkbox to toggle continue mode. If continue mode is on, the BezCurve command will restart after you finish the curve, allowing you to draw another one without pressing the command button again.
- Press DataMake Face
true); if not, the closed wire will not make a face (DataMake Face
false). or click the checkbox to toggle filled mode. If filled mode is on, a closed wire will create a filled face (
- Note: the curve should not be filled if it intersects itself, as it won't create a proper face. If the curve is filled but no shape is visible, manually set DataMake Face to
falseto see the curve.
- Hold snapping your point to the nearest snap location, independently of the distance. while drawing to force
- Hold constrain your next point horizontally or vertically in relation to the last one. while drawing to
- Press + or press the button to undo the last point.
- Press or the button to abort the current command; curve segments already placed will remain.
- A Draft BezCurve can be edited with the Draft Edit command. Nodes can be added, removed and repositioned, and their constraint type can be changed.
- OpenCascade, and therefore FreeCAD, does not support Bézier curves of degrees larger than 25. This should not be a problem in practice, as most users typically use Bézier curves of degrees 3 to 5.
See also: Property editor.
A Draft BezCurve object is derived from a Part Part2DObject and inherits all its properties. It also has the following additional properties:
- DataArea (
Area): (read-only) specifies the area of the face of the curve. The value will be
0.0if DataMake Face if
falseor the face cannot be created.
- DataClosed (
Bool): specifies if the curve is closed or not. If the curve is initially open this value is
false, setting it to
truewill draw a segment to close the curve. If the curve is initially closed this value is
true, setting it to
falsewill remove the last segment and make the curve open.
- DataContinuity (
IntegerList): (read-only) specifies the continuity of the curve.
- DataDegree (
Integer): specifies the degree of the curve.
- DataLength (
Length): (read-only) specifies the total length of the curve.
- DataMake Face (
Bool): specifies if the curve makes a face or not. If it is
truea face is created, otherwise only the perimeter is considered part of the object. This property only works if DataClosed is
trueand if the curve does not self-intersect.
- DataPoints (
VectorList): specifies the control points of the curve in its local coordinate system.
- ViewArrow Size (
Length): specifies the size of the symbol displayed at the end of the curve.
- ViewArrow Type (
Enumeration): specifies the type of symbol displayed at the end of the curve, which can be
- ViewEnd Arrow (
Bool): specifies whether to show a symbol at the end of the curve, so it can be used as an annotation line.
- ViewPattern (
Enumeration): specifies the Draft Pattern with which to fill the face of the closed curve. This property only works if DataMake Face is
trueand if ViewDisplay Mode is
- ViewPattern Size (
Float): specifies the size of the Draft Pattern.
To create a Draft Line use the
make_bezcurve method (introduced in version 0.19) of the Draft module. This method replaces the deprecated
bezcurve = make_bezcurve(pointslist, closed=False, placement=None, face=None, support=None, degree=None) bezcurve = make_bezcurve(Part.Wire, closed=False, placement=None, face=None, support=None, degree=None)
- Creates a
bezcurveobject with the given list of points,
- Each point in the list is defined by its
FreeCAD.Vector, with units in millimeters.
- Alternatively, the input can be a
Part.Wire, from which points are extracted.
- Each point in the list is defined by its
True, or if the first and last points are identical, the curve is closed.
Nonethe shape is created at the origin.
True, and the wire is closed, the wire will make a face, that is, it will appear filled.
import FreeCAD as App import Draft doc = App.newDocument() p1 = App.Vector(0, 0, 0) p2 = App.Vector(1000, 1000, 0) p3 = App.Vector(2000, 0, 0) p4 = App.Vector(1500, -2000, 0) bezcurve1 = Draft.make_bezcurve([p1, p2, p3, p4], closed=True) bezcurve2 = Draft.make_bezcurve([p4, 1.3*p2, p1, 4.1*p3], closed=True) bezcurve3 = Draft.make_bezcurve([1.7*p3, 1.5*p4, 2.1*p2, p1], closed=True) doc.recompute()