Code snippets

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Revision as of 12:06, 19 April 2014 by Mario52 (talk | contribs) (adding "List the PropertiesList")
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This page contains examples, pieces, chunks of FreeCAD python code collected from users experiences and discussions on the forums. Read and use it as a start for your own scripts...

A typical file

Every module must contain, besides your main module file, an file, responsible for inserting the module in the main Gui. This is an example of a simple one.

 class ScriptWorkbench (Workbench): 
     MenuText = "Scripts"
     def Initialize(self):
         import Scripts # assuming is your module
         list = ["Script_Cmd"] # That list must contain command names, that can be defined in
         self.appendToolbar("My Scripts",list) 

A typical module file

This is an example of a main module file, containing everything your module does. It is the file invoked by the previous example. You can have all your custom commands here.

 import FreeCAD, FreeCADGui 
 class ScriptCmd: 
    def Activated(self): 
        # Here your write what your ScriptCmd does...
        FreeCAD.Console.PrintMessage('Hello, World!')
    def GetResources(self): 
        return {'Pixmap' : 'path_to_an_icon/myicon.png', 'MenuText': 'Short text', 'ToolTip': 'More detailed text'} 
 FreeCADGui.addCommand('Script_Cmd', ScriptCmd())

Import a new filetype

Making an importer for a new filetype in FreeCAD is easy. FreeCAD doesn't consider that you import data in an opened document, but rather that you simply can directly open the new filetype. So what you need to do is to add the new file extension to FreeCAD's list of known extensions, and write the code that will read the file and create the FreeCAD objects you want:

This line must be added to the file to add the new file extension to the list:

 # Assumes is the file that has the code for opening and reading .ext files
 FreeCAD.addImportType("Your new File Type (*.ext)","Import_Ext")

Then in the file:

 def open(filename): 
    # here you do all what is needed with filename, read, classify data, create corresponding FreeCAD objects

To export your document to some new filetype works the same way, except that you use:

FreeCAD.addExportType("Your new File Type (*.ext)","Export_Ext") 

Adding a line

A line simply has 2 points.

 import Part,PartGui 
 # add a line element to the document and set its points 

Adding a polygon

A polygon is simply a set of connected line segments (a polyline in AutoCAD). It doesn't need to be closed.

 import Part,PartGui 
 # create a 3D vector, set its coordinates and add it to the list 
 #... repeat for all nodes 
 # Create a polygon object and set its nodes 

Adding and removing an object to a group

 grp=doc.addObject("App::DocumentObjectGroup", "Group") 
 lin=doc.addObject("Part::Feature", "Line")
 grp.addObject(lin) # adds the lin object to the group grp
 grp.removeObject(lin) # removes the lin object from the group grp

Note: You can even add other groups to a group...

Adding a Mesh

 import Mesh
 # create a new empty mesh
 m = Mesh.Mesh()
 # build up box out of 12 facets
 m.addFacet(0.0,0.0,0.0, 0.0,0.0,1.0, 0.0,1.0,1.0)
 m.addFacet(0.0,0.0,0.0, 0.0,1.0,1.0, 0.0,1.0,0.0)
 m.addFacet(0.0,0.0,0.0, 1.0,0.0,0.0, 1.0,0.0,1.0)
 m.addFacet(0.0,0.0,0.0, 1.0,0.0,1.0, 0.0,0.0,1.0)
 m.addFacet(0.0,0.0,0.0, 0.0,1.0,0.0, 1.0,1.0,0.0)
 m.addFacet(0.0,0.0,0.0, 1.0,1.0,0.0, 1.0,0.0,0.0)
 m.addFacet(0.0,1.0,0.0, 0.0,1.0,1.0, 1.0,1.0,1.0)
 m.addFacet(0.0,1.0,0.0, 1.0,1.0,1.0, 1.0,1.0,0.0)
 m.addFacet(0.0,1.0,1.0, 0.0,0.0,1.0, 1.0,0.0,1.0)
 m.addFacet(0.0,1.0,1.0, 1.0,0.0,1.0, 1.0,1.0,1.0)
 m.addFacet(1.0,1.0,0.0, 1.0,1.0,1.0, 1.0,0.0,1.0)
 m.addFacet(1.0,1.0,0.0, 1.0,0.0,1.0, 1.0,0.0,0.0)
 # scale to a edge langth of 100
 # add the mesh to the active document

Adding an arc or a circle

 import Part
 doc = App.activeDocument()
 c = Part.Circle() 
 f = doc.addObject("Part::Feature", "Circle") # create a document with a circle feature 
 f.Shape = c.toShape() # Assign the circle shape to the shape property 

Accessing and changing representation of an object

Each object in a FreeCAD document has an associated view representation object that stores all the parameters that define how the object appear, like color, linewidth, etc...

 gad=Gui.activeDocument()   # access the active document containing all 
                           # view representations of the features in the
                           # corresponding App document 
 v=gad.getObject("Cube")    # access the view representation to the Mesh feature 'Cube' 
 v.ShapeColor               # prints the color to the console 
 v.ShapeColor=(1.0,1.0,1.0) # sets the shape color to white

Observing mouse events in the 3D viewer via Python

The Inventor framework allows to add one or more callback nodes to the scenegraph of the viewer. By default in FreeCAD one callback node is installed per viewer which allows to add global or static C++ functions. In the appropriate Python binding some methods are provided to make use of this technique from within Python code.

 #This class logs any mouse button events. As the registered callback function fires twice for 'down' and
 #'up' events we need a boolean flag to handle this.
 class ViewObserver:
    def logPosition(self, info):
        down = (info["State"] == "DOWN")
        pos = info["Position"]
        if (down):
            FreeCAD.Console.PrintMessage("Clicked on position: ("+str(pos[0])+", "+str(pos[1])+")\n")
 o = ViewObserver()
 c = v.addEventCallback("SoMouseButtonEvent",o.logPosition)

Now, pick somewhere on the area in the 3D viewer and observe the messages in the output window. To finish the observation just call


The following event types are supported

  • SoEvent -- all kind of events
  • SoButtonEvent -- all mouse button and key events
  • SoLocation2Event -- 2D movement events (normally mouse movements)
  • SoMotion3Event -- 3D movement events (normally spaceball)
  • SoKeyboardEvent -- key down and up events
  • SoMouseButtonEvent -- mouse button down and up events
  • SoSpaceballButtonEvent -- spaceball button down and up events

The Python function that can be registered with addEventCallback() expects a dictionary. Depending on the watched event the dictionary can contain different keys.

For all events it has the keys:

  • Type -- the name of the event type i.e. SoMouseEvent, SoLocation2Event, ...
  • Time -- the current time as string
  • Position -- a tuple of two integers, mouse position
  • ShiftDown -- a boolean, true if Shift was pressed otherwise false
  • CtrlDown -- a boolean, true if Ctrl was pressed otherwise false
  • AltDown -- a boolean, true if Alt was pressed otherwise false

For all button events, i.e. keyboard, mouse or spaceball events

  • State -- A string 'UP' if the button was up, 'DOWN' if it was down or 'UNKNOWN' for all other cases

For keyboard events:

  • Key -- a character of the pressed key

For mouse button event

  • Button -- The pressed button, could be BUTTON1, ..., BUTTON5 or ANY

For spaceball events:

  • Button -- The pressed button, could be BUTTON1, ..., BUTTON7 or ANY

And finally motion events:

  • Translation -- a tuple of three floats
  • Rotation -- a quaternion for the rotation, i.e. a tuple of four floats

Manipulate the scenegraph in Python

It is also possible to get and change the scenegraph in Python, with the 'pivy' module -- a Python binding for Coin.

 from pivy.coin import *                # load the pivy module
 view = Gui.ActiveDocument.ActiveView   # get the active viewer
 root = view.getSceneGraph()            # the root is an SoSeparator node

The Python API of pivy is created by using the tool SWIG. As we use in FreeCAD some self-written nodes you cannot create them directly in Python. However, it is possible to create a node by its internal name. An instance of the type 'SoFCSelection' can be created with

 type = SoType.fromName("SoFCSelection")
 node = type.createInstance()

Adding and removing objects to/from the scenegraph

Adding new nodes to the scenegraph can be done this way. Take care of always adding a SoSeparator to contain the geometry, coordinates and material info of a same object. The following example adds a red line from (0,0,0) to (10,0,0):

 from pivy import coin
 sg = Gui.ActiveDocument.ActiveView.getSceneGraph()
 co = coin.SoCoordinate3()
 pts = [[0,0,0],[10,0,0]]
 ma = coin.SoBaseColor()
 ma.rgb = (1,0,0)
 li = coin.SoLineSet()
 no = coin.SoSeparator()

To remove it, simply issue:


Adding custom widgets to the interface

You can create custom widgets with Qt designer, transform them into a python script, and then load them into the FreeCAD interface with PyQt4.

The python code produced by the Ui python compiler (the tool that converts qt-designer .ui files into python code) generally looks like this (it is simple, you can also code it directly in python):

 class myWidget_Ui(object):
  def setupUi(self, myWidget):
    myWidget.setObjectName("my Nice New Widget")
    myWidget.resize(QtCore.QSize(QtCore.QRect(0,0,300,100).size()).expandedTo(myWidget.minimumSizeHint())) # sets size of the widget
    self.label = QtGui.QLabel(myWidget) # creates a label
    self.label.setGeometry(QtCore.QRect(50,50,200,24)) # sets its size
    self.label.setObjectName("label") # sets its name, so it can be found by name
  def retranslateUi(self, draftToolbar): # built-in QT function that manages translations of widgets
    myWidget.setWindowTitle(QtGui.QApplication.translate("myWidget", "My Widget", None, QtGui.QApplication.UnicodeUTF8))
    self.label.setText(QtGui.QApplication.translate("myWidget", "Welcome to my new widget!", None, QtGui.QApplication.UnicodeUTF8))

Then, all you need to do is to create a reference to the FreeCAD Qt window, insert a custom widget into it, and "transform" this widget into yours with the Ui code we just made:

  app = QtGui.qApp
  FCmw = app.activeWindow() # the active qt window, = the freecad window since we are inside it
  myNewFreeCADWidget = QtGui.QDockWidget() # create a new dckwidget
  myNewFreeCADWidget.ui = myWidget_Ui() # load the Ui script
  myNewFreeCADWidget.ui.setupUi(myNewFreeCADWidget) # setup the ui
  FCmw.addDockWidget(QtCore.Qt.RightDockWidgetArea,myNewFreeCADWidget) # add the widget to the main window

Adding a Tab to the Combo View

The following code allows you to add a tab to the FreeCAD ComboView, besides the "Project" and "Tasks" tabs. It also uses the uic module to load an ui file directly in that tab.

 from PyQt4 import QtGui,QtCore
 from PyQt4 import uic
 #from PySide import QtGui,QtCore
 def getMainWindow():
    "returns the main window"
    # using QtGui.qApp.activeWindow() isn't very reliable because if another
    # widget than the mainwindow is active (e.g. a dialog) the wrong widget is
    # returned
    toplevel = QtGui.qApp.topLevelWidgets()
    for i in toplevel:
        if i.metaObject().className() == "Gui::MainWindow":
            return i
    raise Exception("No main window found")
 def getComboView(mw):
    for i in dw:
        if str(i.objectName()) == "Combo View":
            return i.findChild(QtGui.QTabWidget)
    raise Exception("No tab widget found")
 mw = getMainWindow()
 tab = getComboView(getMainWindow())
 tab.addTab(tab2,"A Special Tab")

Opening a custom webpage

 import WebGui

Getting the HTML contents of an opened webpage

 from PyQt4 import QtGui,QtWebKit
 a = QtGui.qApp
 mw = a.activeWindow()
 v = mw.findChild(QtWebKit.QWebFrame)
 html = unicode(v.toHtml())
 print html

Retrieve and use the coordinates of 3 selected points or objects

# -*- coding: utf-8 -*-
# the line above to put the accentuated in the remarks
# If this line is missing, an error will be returned
# extract and use the coordinates of 3 objects selected
import Part, FreeCAD, math, PartGui, FreeCADGui
from FreeCAD import Base, Console
sel = FreeCADGui.Selection.getSelection() # " sel " contains the items selected
if len(sel)!=3 :
  # If there are no 3 objects selected, an error is displayed in the report view
  # The \r and \n at the end of line mean return and the newline CR + LF.
  Console.PrintError("Select 3 points exactly\r\n")
else :
  for obj in sel:

  for pt in points:
    # display of the coordinates in the report view

  Console.PrintMessage(str(pt[1]) + "\r\n")

List all objects

# -*- coding: utf-8 -*-
# List all objects
doc = FreeCAD.ActiveDocument
objs = FreeCAD.ActiveDocument.Objects
#print objs
#print len(FreeCAD.ActiveDocument.Objects)
for obj in objs:
    name = obj.Name        # list the names of the objects
    print name             # Displays the name of the object
#doc.removeObject("Ortho") # Clears the designated object

Function resident with the mouse click action

# -*- coding: utf-8 -*-
# causes an action to the mouse click on an object
# This function remains resident (in memory) with the function "addObserver(s)"
# "removeObserver(s) # Uninstalls the resident function
class SelObserver:
    def addSelection(self,doc,obj,sub,pnt):  # Selection
        print "addSelection"
        print doc                            # Name of the document
        print obj                            # Name of the object
        print sub                            # The part of the object name
        print pnt                            # Coordinates of the object

    def removeSelection(self,doc,obj,sub):   # Delete the selected object
        print "removeSelection"
    def setSelection(self,doc):              # Selection in ComboView
        print "setSelection"
    def clearSelection(self,doc):            # If click on the screen, clear the selection
        print "clearSelection"               # If click on another object, clear the previous object

FreeCADGui.Selection.addObserver(s)    # install the function mode resident
#FreeCADGui.Selection.removeObserver(s) # Uninstall the resident function

List the components of an object

# -*- coding: utf-8 -*-
# This function list the components of an object
# and extract this object its XYZ coordinates,
# its edges and their lengths
# its faces and their surfaces

import Draft,Part
def detail():
    sel = FreeCADGui.Selection.getSelection()   # Select an object
    if len(sel) != 0:                           # If there is a selection then
        pas    =0

        for num in sel[0].Shape.Vertexes:       # Search the XYZ coordinates and displays
            if pas == 0:                        
                Vertx.append("X1: "+str(num.Point[0]))
                Vertx.append("Y1: "+str(num.Point[1]))
                Vertx.append("Z1: "+str(num.Point[2]))
                print "X1: "+str(num.Point[0])," Y1: "+str(num.Point[1])," Z1: "+str(num.Point[2]),
                Vertx.append("X2: "+str(num.Point[0]))
                Vertx.append("Y2: "+str(num.Point[1]))
                Vertx.append("Z2: "+str(num.Point[2]))
                print " X2: "+str(num.Point[0])," Y2: "+str(num.Point[1])," Z2: "+str(num.Point[2])
        print "Number of Vertex       : ", compt_V
        perimetre = 0.0   
        EdgesLong = []

        for j in enumerate(sel[0].Shape.Edges):                                     # Search the "Edges" and their lengths
            Edges.append("Edge%d" % (j[0]+1))
            perimetre += (sel[0].Shape.Edges[compt_E-1].Length)                      # calculates the perimeter
            print "Edge",str(compt_E)," > ",str(sel[0].Shape.Edges[compt_E-1].Length)# Displays the "Edge" and its length
        print "Perimeter of the form  : ",perimetre

        FacesSurf = []
        for j in enumerate(sel[0].Shape.Faces):                                      # Search the "Faces" and their surface
            Faces.append("Face%d" % (j[0]+1))
            print "Face",str(compt_F)," > ",sel[0].Shape.Faces[compt_F-1].Area       # Displays 'Face' and its surface
        print "Surface of the form    : ",sel[0].Shape.Area                          # Displays the total surface of the form


List the PropertiesList

o = App.ActiveDocument.ActiveObject
op = o.PropertiesList
for p in op:
    print "Property: ", p, " Value: ", o.getPropertyByName (p)
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