Macro Make Arc 3 Points

Description

This macro creates a arc on 3 selected points.

Use

Launch the macro, select 3 points, the arc is created and the coordinates and the length of the arc are displayed in the report view.

(PS: It is not required to hold down the Ctrl key)

Script

The icon for the toolBar

Macro_Make_Arc_3_Points.FCMacro

# -*- coding: utf-8 -*-
from FreeCAD import Base

__title__   = "Macro_Make_Arc_3_points"
__author__  = "Mario52"
__url__     = "http://www.freecadweb.org/index-fr.html"
__version__ = "00.01"
__date__    = "14/07/2016"

global selected; selected = []
App = FreeCAD

class SelObserver:
    print "Create Arc to 3 points ..."
    def addSelection(self,doc,obj,sub,pnt):  # Selection 
        global selected
        selected.append(pnt)
        if len(selected) == 1:
            print "Point 1 : ",FreeCAD.Vector(selected[0])
        elif len(selected) == 2:
            print "Point 2 : ",FreeCAD.Vector(selected[1])
        elif len(selected) == 3:
            print "Point 3 : ",FreeCAD.Vector(selected[2])
            try:
                C1 = Part.Arc(FreeCAD.Vector(selected[0]),FreeCAD.Vector(selected[1]),FreeCAD.Vector(selected[2]))
                S1 = Part.Shape([C1])
                W = Part.Wire(S1.Edges)
                Part.show(W)
                App.ActiveDocument.ActiveObject.Label   = "Arc_3_Points"
                print "Length  : ",W.Length
            except Exception:
                print "Three points are collinear or bad selection"
            del selected[:]
            FreeCADGui.Selection.removeObserver(s)
            print "End Make_Arc_3_Points"
            print "_____________________"

s=SelObserver()
FreeCADGui.Selection.addObserver(s)