src/Mod/PartDesign/Scripts/Spring.py

#! python
# (c) 2011 Adrian Przekwas LGPL

from __future__ import division  # allows floating point division from integers
import FreeCAD, Part
from FreeCAD import Base


class MySpring:
    def __init__(self, obj):
        """Add the properties: Pitch, Diameter, Height, BarDiameter"""
        obj.addProperty(
            "App::PropertyLength", "Pitch", "MySpring", "Pitch of the helix", locked=True
        ).Pitch = 5.0
        obj.addProperty(
            "App::PropertyLength", "Diameter", "MySpring", "Diameter of the helix", locked=True
        ).Diameter = 6.0
        obj.addProperty(
            "App::PropertyLength", "Height", "MySpring", "Height of the helix", locked=True
        ).Height = 30.0
        obj.addProperty(
            "App::PropertyLength", "BarDiameter", "MySpring", "Diameter of the bar", locked=True
        ).BarDiameter = 3.0
        obj.Proxy = self

    def onChanged(self, fp, prop):
        if prop == "Pitch" or prop == "Diameter" or prop == "Height" or prop == "BarDiameter":
            self.execute(fp)

    def execute(self, fp):
        pitch = fp.Pitch
        radius = fp.Diameter / 2
        height = fp.Height
        barradius = fp.BarDiameter / 2
        myhelix = Part.makeHelix(pitch, height, radius)
        g = myhelix.Edges[0].Curve
        c = Part.Circle()
        c.Center = g.value(0)  # start point of the helix
        c.Axis = (0, 1, 0)
        c.Radius = barradius
        p = c.toShape()
        section = Part.Wire([p])
        makeSolid = True
        isFrenet = True
        myspring = Part.Wire(myhelix).makePipeShell([section], makeSolid, isFrenet)
        fp.Shape = myspring


def makeMySpring():
    doc = FreeCAD.activeDocument()
    if doc is None:
        doc = FreeCAD.newDocument()
    spring = doc.addObject("Part::FeaturePython", "My_Spring")
    spring.Label = "My Spring"
    MySpring(spring)
    spring.ViewObject.Proxy = 0
    doc.recompute()


if __name__ == "__main__":
    makeMySpring()