Surface ExtendFace

    From FreeCAD Documentation
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    Surface ExtendFace.svg Surface ExtendFace

    Menu location
    Surface → Extend face
    Workbenches
    Surface
    Default shortcut
    None
    Introduced in version
    0.17
    See also
    None

    Description

    Surface ExtendFace.svg Surface ExtendFace extrapolates an existing face or surface at its boundaries with its local U and V parameters.

    Surface ExtendFace base example.png Surface ExtendFace example.png

    Left: original face. Right: extended face.

    Usage

    1. Make sure you have an object that has faces. The object could be created with the Workbench Surface.svg Surface Workbench but it could also be any other object, for example, created with Workbench Part.svg Part or Workbench PartDesign.svg PartDesign.
    2. Select the face to extend by clicking on it on the 3D view.
    3. Press Surface ExtendFace.svg Extend face.

    Options

    This command doesn't have any options. Either it works with the selection or not.

    Properties

    A Surface Extend object (Surface::Extend class) is derived from the basic Part Feature (Part::Feature class, through the Part::Spline subclass), therefore it shares all the latter's properties.

    In addition to the properties described in Part Feature, the Surface Filling has the following properties in the property editor.

    Data

    Base

    • DataFace (LinkSub): the subelement from an object that will be extended; it must be a face.
    • DataTolerance (FloatConstraint): it defaults to 0.1.
    • DataExtend UNeg (FloatConstraint): it defaults to 0.05. The ratio of the local U parameter that will be extended in the negative direction.
    • DataExtend UPos (FloatConstraint): it defaults to 0.05. The ratio of the local U parameter that will be extended in the positive direction.
    • DataExtend USymetric (Bool): it defaults to true, in which case DataExtend UNeg and DataExtend UPos will have the same value.
    • DataExtend VNeg (FloatConstraint): it defaults to 0.05. The ratio of the local V that will be extended in the negative direction.
    • DataExtend VPos (FloatConstraint): it defaults to 0.05. The ratio of the local V direction that will be extended in the positive direction.
    • DataExtend VSymetric (Bool): it defaults to true, in which case DataExtend VNeg and DataExtend VPos will have the same value.
    • DataSampleU (IntegerConstraint): it defaults to 32.
    • DataSampleV (IntegerConstraint): it defaults to 32.

    View

    Base

    • ViewControl Points (Bool): it defaults to false; if set to true, it will show an overlay with the control points of the surface.

    Scripting

    See also: FreeCAD Scripting Basics.

    The Surface Extend tool can be used in macros and from the Python console by adding the Surface::Extend object.

    • The face to extend must be assigned as a LinkSub to the Face property of the object. It must contain only a single face.
    import FreeCAD as App
    import Draft
    
    doc = App.newDocument()
    
    a = App.Vector(-20, -20, 0)
    b = App.Vector(-18, 25, 0)
    c = App.Vector(60, 26, 0)
    d = App.Vector(33, -20, 0)
    
    points = [a, App.Vector(-20, -8, 0), b, c,
              App.Vector(37, 4, 0), d,
              App.Vector(-2, -18, 0), a]
    obj = Draft.make_bspline(points)
    doc.recompute()
    
    if App.GuiUp:
        obj.ViewObject.Visibility = False
    
    surf = doc.addObject("Surface::Filling", "Surface")
    surf.BoundaryEdges = [(obj, "Edge1")]
    doc.recompute()
    
    # ---------------------------------------------------------
    points_spl = [App.Vector(-10, 0, 2),
                  App.Vector(4, 0, 7),
                  App.Vector(18, 0, -5),
                  App.Vector(25, 0, 0),
                  App.Vector(30, 0, 0)]
    aux_edge = Draft.make_bspline(points_spl)
    doc.recompute()
    
    surf.UnboundEdges = [(aux_edge, "Edge1")]
    doc.recompute()
    
    # ---------------------------------------------------------
    surf_extended = doc.addObject("Surface::Extend", "Surface")
    surf_extended.Face = [surf, "Face1"]
    doc.recompute()