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Description

This macro positions an object perpendicularly to the selected wire.

Usage

1. Install the macro via the Addon Manager
2. Select the path (may be an element or sub-element)
3. Select the object to align
4. Execute the macro

Script

The macro toolbar icon:

Macro Perpendicular To Wire.FCMacro

# -*- coding: utf-8 -*-
__title__   = "Macro Perpendicular To Wire"
__author__  = "Mario52"
__url__     = "https://wiki.freecad.org/Macro_Perpendicular_To_Wire"
__version__ = "00.03"
__date__    = "31/03/2020"

import Draft, Part

try:
    sel = FreeCADGui.Selection.getSelection()                               # Select an object
    
    lineSelected = FreeCADGui.Selection.getSelectionEx()[0].SubObjects[0]   # first object the Path object or SubObjects
    myCircle     = sel[1]                                                   # second object
    
    pointsDirection  = []
    
    pointsDirection = lineSelected.discretize(Number=500)                   # discretize the path line first selection
    
    v=pointsDirection[0].sub(pointsDirection[1])                            # avec vecteurs 1 et 2 (direction debut ligne)
    r=App.Rotation(App.Vector(0,0,1),v)
    
    pl=FreeCAD.Placement()                                                  # placement object
    pl.Rotation.Q = r.Q
    pl.Base = pointsDirection[0]
    myCircle.Placement = pl
    
    del pointsDirection[:]
    FreeCAD.ActiveDocument.recompute()
except Exception:
    print( "Select two objects. 1:The path 2:The object to align" )

Options

Essentially the line is cut in x points with discretize() (for our purposes we default to Number=500 but cuts may be modfied between 0 to 499)

pointsDirection = lineSelected.Shape.discretize(Number=500)             # discretize the path line first selection

1. The perpendicularity is calculated between 2 points:

v=pointsDirection[0].sub(pointsDirection[1])          # perpendicular of first > second point

2:

v=pointsDirection[-1].sub(pointsDirection[-2])       # perpendicular of last > before last point
pl.Base = pointsDirection[-1]                        # position base last point

3:

v=pointsDirection[100].sub(pointsDirection[101])   # perpendicular of point 100 > point 101
pl.Base = pointsDirection[100]                     # position base point 100

4:

v=pointsDirection[0].sub(pointsDirection[-1])         # perpendicular of first point > last point
pl.Base = pointsDirection[0]                          # position base first point

Other parameters to discretize() are as follows:

# Discretizes the edge and returns a list of points.
# Forum thread: https://forum.freecad.org/viewtopic.php?f=12&t=16336#p129468
# The function accepts keywords as argument:
# discretize(Number=n) => gives a list of 'n' equidistant points
# discretize(QuasiNumber=n) => gives a list of 'n' quasi equidistant points (is faster than the method above)
# discretize(Distance=d) => gives a list of equidistant points with distance 'd'
# discretize(Deflection=d) => gives a list of points with a maximum deflection 'd' to the edge
# discretize(QuasiDeflection=d) => gives a list of points with a maximum deflection 'd' to the edge (faster)
# discretize(Angular=a,Curvature=c,[Minimum=m]) => gives a list of points with an angular deflection of 'a'
# and a curvature deflection of 'c'. Optionally a minimum number of points
# can be set which by default is set to 2.

Example

Discussions

• [Spiralbohrer] discussion on the FC forum.
• https://forum.freecad.org/viewtopic.php?f=12&t=16336#p129468

Version

Ver 00.03 2020-03-21: Source and comment typo fixes Ver 00.02 2019-04-06: Python 3