Draft BSpline

Description
The BSpline tool creates a B-Spline curve from several points. It uses the Draft Linestyle set on the Draft Tray.

The BSpline tool behaves like the Draft Wire tool, except that each of its segments is curved instead of being a straight line. The BSpline tool specifies the exact points through which the curve will go; on the other hand the Draft BezCurve tool uses to define the direction of the curve. To create exact circular or elliptical curves, use Draft Arc and Draft Ellipse.



How to use

 * 1) Press the  button, or press  then  keys
 * 2) Click a first point on the 3D view, or type a coordinate and press the  button.
 * 3) Click additional points on the 3D view, or type a coordinate and press the  button.
 * 4) Press  or the  button to complete the edition.

The spline can be edited by double clicking on the element in the tree view, or by pressing the button. Move the points around to a new position, or click or  and then click on the wire to add or remove points.

Options

 * Press or the  button to finish the spline, leaving it open.
 * Press or the  button to close the spline, that is, a curve will be added from the last point to the first one to form a face. At least three points are required to form a face.
 * Press or the  button to remove the curve segments already placed, but keep editing the spline 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. You can press the  button when you have the desired values to insert the point.
 * 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 BSpline tool will restart after you finish the spline, allowing you to draw another one without pressing the tool button again.
 * Press or click the checkbox to toggle filled mode. If filled mode is on, a closed spline will create a filled face ; if not, the closed spline will not make a face.
 * the spline should not be filled if it intersects itself, as it won't create a proper face. If the spline is filled but no shape is visible, manually set to  to see the spline.


 * Press while drawing to force snapping your point to the nearest snap location, independently of the distance.
 * Press while drawing to constrain your next point horizontally or vertically in relation to the last one.
 * 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.

Properties
A BSpline object shares most properties from a Draft Wire, however, most properties only make sense for a Wire.

Data

 * : specifies if the spline is closed or not. If the spline is initially open, this value is ; setting it to will draw a curve segment to close the spline. If the spline is initially closed, this value is ; setting it to  will remove the last curve segment, and make the spline open.
 * : specifies if the spline makes a face or not. If it is a face is created, otherwise only the perimeter is considered part of the object. This property only works if  is.
 * do not set to  if the spline intersects itself, as it won't create a proper face.


 * : affects the shape of the BSpline.

View

 * : specifies the size of the symbol displayed at the end of the spline.
 * : specifies the type of symbol displayed at the end of the spline, which can be "Dot", "Circle", "Arrow", or "Tick".
 * : specifies whether to show a symbol at the last point of the spline, so it can be used as an annotation line.
 * : specifies a Draft Pattern with which to fill the face of a closed spline. This property only works if is, and if  is "Flat Lines".
 * : specifies the size of the Draft Pattern.

Scripting
FreeCAD Scripting Basics, Draft API, and the autogenerated API documentation.

The BSpline tool can be used in macros and from the Python console by using the following function:


 * Creates a object from the given list of points,.
 * Each point in the list is defined by its, with units in millimeters.
 * Alternatively, the input can be a, from which points are extracted.
 * If is, or if the first and last points are identical, the wire is closed.
 * If a is given, it is used; otherwise the shape is created at the origin.
 * If is, and the spline is closed, the spline will make a face, that is, it will appear filled.

Example: