Code snippets

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Base ExampleCommandModel.png Руководство

Тема
Python
уровень
Beginner
Время для завершения
автор
FreeCAD версия
Пример файла (ов)

Contents


Эта страница содержит примеры, обрывки, куски FreeCAD python кода, собранный для получения пользователями оптыта и обсуждения на форумах. Читайте и используете их как начало для ваших собственных сценариев...

Обычный файл InitGui.py

Каждый модуль должен содержать, помимо основного файла модуля, файл InitGui.py , ответственного за вставку модуля в главное Gui. Это простой пример

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

Обычный файл модуля

Это пример головного файла модуля, содержащего всё что ваш модуль делает. Это Scripts.py файл вызванный в предыдущем примере. Вы можете установить здесь все ваши пользовательские команды.

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())

Импорт нового типа файлов

Создание ипортировщика в нового типа файлов в FreeCAD, просто. FreeCAD не считает что вы импортируете данные в открытый документ, а скорее что вы просто можете непосредственно открыть новый тип файла. Так что все что вам нужно сделать, это добавить новое расширение файла в список известных расширений FreeCAD , и написать код, который будет читать файл и создавать FreeCAD объекты:

Это строка должна быть добавлена в InitGui.py файл для добавления нового расширения файлов в список:

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

Тогда в файле Import_Ext.py:

def open(filename): 
   doc=App.newDocument()
   # here you do all what is needed with filename, read, classify data, create corresponding FreeCAD objects
   doc.recompute()

Экспорт вашего документа в новые типы файлов работает схожим образом, исключая того что вы используете:

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

Добавление линии

Простейшая линия через две точки.

import Part,PartGui 
doc=App.activeDocument() 
# add a line element to the document and set its points 
l=Part.LineSegment()
l.StartPoint=(0.0,0.0,0.0)
l.EndPoint=(1.0,1.0,1.0)
doc.addObject("Part::Feature","Line").Shape=l.toShape() 
doc.recompute()

Добавление многоугольника

Многоугольник это просто набор соединенных отрезков (polyline в AutoCAD). Он необязательно должен быть замкнутым.

import Part,PartGui 
doc=App.activeDocument()
n=list() 
# create a 3D vector, set its coordinates and add it to the list 
v=App.Vector(0,0,0) 
n.append(v) 
v=App.Vector(10,0,0) 
n.append(v) 
#... repeat for all nodes 
# Create a polygon object and set its nodes 
p=doc.addObject("Part::Polygon","Polygon") 
p.Nodes=n 
doc.recompute()

Добавление и удаление объекта из группы

doc=App.activeDocument() 
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

Примечание: Вы также можете добавлять другие группы в группу...

Добавление Полигиональной модели

import Mesh
doc=App.activeDocument()
# 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
m.scale(100.0)
# add the mesh to the active document
me=doc.addObject("Mesh::Feature","Cube")
me.Mesh=m

Добавление дуги или огружности

import Part
doc = App.activeDocument()
c = Part.Circle() 
c.Radius=10.0  
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 
doc.recompute()

Получение доступа и изменение представления объекта

Каждый объект в FreeCAD документе оссоциируется с визуальным представлением объекта, которое хранит все параметры , определяющие как объект представлен, такие как цвет, длина линий, и.т.д...

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

Наблюдение за поведение мыши в 3D окне через Python

Inventor позваляет добавить оди и более узлов обратного вызова(callback) в дерево сцен просмотрщика. По умолчанию в FreeCAD один узел обратного вызова установлен в кадое окно просмотра(просмотрщик), который позволяет добавить глобальные или статические C++ функции. Соответствуюе Python привязки, некоторые методы которых позволяют использовать эту технику (callback) в Python коде.

App.newDocument()
v=Gui.activeDocument().activeView()
 
#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)

Теперь, выберите какую нибудь область в окне 3D-просмотра и наблюдайте сообщения в окне вывода. Для завершения наблюдения просто вызовите

v.removeEventCallback("SoMouseButtonEvent",c)

Поддерживаются следующие типы событий

  • SoEvent -- Все события
  • SoButtonEvent -- Все события клавиш клавиатуры и мыши
  • SoLocation2Event -- события 2D перемещений (обычно движение мыши)
  • SoMotion3Event -- события 3D перемещений (обычно spaceball)
  • SoKeyboradEvent -- события нажатие и отпускание клавиш клавиатуры
  • SoMouseButtonEvent -- события нажатия и отпускания клавиш мыши
  • SoSpaceballButtonEvent -- события нажатия и отпускания клавиш spaceball

Python функции которые могут быть зарегистрированы в addEventCallback() предлагающем словарь(dictionary). В зависимости от наблюдателя события словарь может содержать различные ключи.

Для всех событий существуют ключи:

  • Type -- Имя типа события т.е. SoMouseEvent, SoLocation2Event, ...
  • Time -- текущие время в виде строки
  • Position -- набор из двух целых чисел как позиция курсорa мыши
  • ShiftDown -- логическая(boolean) переменная, true если Shift нажат, в противном случае false
  • CtrlDown -- логическая(boolean) переменная, true если Ctrl нажат, в противном случае false
  • AltDown -- логическая(boolean) переменная, true если Alt нажат, в противном случае false

Для всех клавишных событий, т.e. для событий клавиатуры, мыши или spaceball

  • State -- Строка 'UP' если кнопка была вверху, 'DOWN' если кнопка была внизу или 'UNKNOWN' во всех остальных случаях

Для событий связанных с клавиатурой:

  • Key -- значение нажатоой клаывиши

Для событий связанных с мышью

  • Button -- Нажаты клавиши, могут быть BUTTON1, ..., BUTTON5 или ANY

Для событий spaceball:

  • Button -- Нажатые клавиши, могут быть BUTTON1, ..., BUTTON7 или ANY

и наконец события движения:

  • Translation -- набор из трех переменных floats
  • Rotation -- кватернион поворота, т.е. набор из четырех переменных floats

Display keys pressed and Events command

This macro displays in the report view the keys pressed and all events command

App.newDocument()
v=Gui.activeDocument().activeView()
class ViewObserver:
   def logPosition(self, info):
       try:
           down = (info["Key"])
           FreeCAD.Console.PrintMessage(str(down)+"\n") # here the character pressed
           FreeCAD.Console.PrintMessage(str(info)+"\n") # list all events command
           FreeCAD.Console.PrintMessage("_______________________________________"+"\n")
       except Exception:
           None
 
o = ViewObserver()
c = v.addEventCallback("SoEvent",o.logPosition)

#v.removeEventCallback("SoEvent",c) # remove ViewObserver

Манипулирование scenegraph в Python

Кроме того можно получить и изменить граф сцены в Python, с помощью модуля 'pivy' -- Python привязки к 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
root.addChild(SoCube())
view.fitAll()

Python API для pivy создано используя инструмент SWIG. Так как мы используем в FreeCAD некоторые самостоятельно записанные узлы вы не можете создавать их напрямую через Python. Однако, возможно создать узел в его внутренним именем. Экземпляр типа 'SoFCSelection' может быть создан

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

Добавление и удаление объектов в/из графа сцены

Добавление новых узлов в граф сцены(scenegraph) может сделать таким образом. Всегда заботтесь о добавлении SoSeparator содержащего информацию о геометрии, координатах и материалах объекта. В следующем примере добавляется красная линия из точки (0,0,0) в (10,0,0):

from pivy import coin
sg = Gui.ActiveDocument.ActiveView.getSceneGraph()
co = coin.SoCoordinate3()
pts = [[0,0,0],[10,0,0]]
co.point.setValues(0,len(pts),pts)
ma = coin.SoBaseColor()
ma.rgb = (1,0,0)
li = coin.SoLineSet()
li.numVertices.setValue(2)
no = coin.SoSeparator()
no.addChild(co)
no.addChild(ma)
no.addChild(li)
sg.addChild(no)

Чтобы удалить её, просто введите:

sg.removeChild(no)

Saves the sceneGraph with a rotation in a series of 36 files in the X Y Z axis

import math
import time
from FreeCAD import Base
from pivy import coin

size=(1000,1000)
dirname = "C:/Temp/animation/"
steps=36
angle=2*math.pi/steps

matX=Base.Matrix()
matX.rotateX(angle)
stepsX=Base.Placement(matX).Rotation

matY=Base.Matrix()
matY.rotateY(angle)
stepsY=Base.Placement(matY).Rotation

matZ=Base.Matrix()
matZ.rotateZ(angle)
stepsZ=Base.Placement(matZ).Rotation

view=Gui.ActiveDocument.ActiveView
cam=view.getCameraNode()
rotCamera=Base.Rotation(*cam.orientation.getValue().getValue())

# this sets the lookat point to the center of circumsphere of the global bounding box
view.fitAll()

# the camera's position, i.e. the user's eye point
position=Base.Vector(*cam.position.getValue().getValue())
distance=cam.focalDistance.getValue()

# view direction
vec=rotCamera.multVec(Base.Vector(0,0,-1))

# this is the point on the screen the camera looks at
# when rotating the camera we should make this point fix
lookat=position+vec*distance

# around x axis
for i in range(steps):
    rotCamera=stepsX.multiply(rotCamera)
    cam.orientation.setValue(*rotCamera.Q)
    vec=rotCamera.multVec(Base.Vector(0,0,-1))
    pos=lookat-vec*distance
    cam.position.setValue(pos.x,pos.y,pos.z)
    Gui.updateGui()
    time.sleep(0.3)
    view.saveImage(dirname+"x-%d.png" % i,*size)

# around y axis
for i in range(steps):
    rotCamera=stepsY.multiply(rotCamera)
    cam.orientation.setValue(*rotCamera.Q)
    vec=rotCamera.multVec(Base.Vector(0,0,-1))
    pos=lookat-vec*distance
    cam.position.setValue(pos.x,pos.y,pos.z)
    Gui.updateGui()
    time.sleep(0.3)
    view.saveImage(dirname+"y-%d.png" % i,*size)

# around z axis
for i in range(steps):
    rotCamera=stepsZ.multiply(rotCamera)
    cam.orientation.setValue(*rotCamera.Q)
    vec=rotCamera.multVec(Base.Vector(0,0,-1))
    pos=lookat-vec*distance
    cam.position.setValue(pos.x,pos.y,pos.z)
    Gui.updateGui()
    time.sleep(0.3)
    view.saveImage(dirname+"z-%d.png" % i,*size)

Добавление пользовательских виджетов к интерфейсу

Вы можете содать собственные виджеты с помощью Qt designer, превратив их в сценарии на python, с помощью PySide, и загрузив их в FreeCAD.

Python код созданный с помощью Ui python compiler (это инструмент для конвертирования файлов ui. созданных qt-designer в python код) в основном выглядит так (это простой пример, вы также может писать этот код напряму с помощью 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))

Тогда все что вам нужно сделать, это создать ссылку на FreeCAD Qt окно, вставить виджет в него, и "преобразовать" этот виджет в ваш с Ui кодом который мы только что сделали:

app = QtGui.qApp
FCmw = app.activeWindow() # the active qt window, = the freecad window since we are inside it
# FCmw = FreeCADGui.getMainWindow() # use this line if the 'addDockWidget' error is declared
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.

# create new Tab in ComboView
from PySide import QtGui,QtCore
#from PySide import uic

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):
   dw=mw.findChildren(QtGui.QDockWidget)
   for i in dw:
       if str(i.objectName()) == "Combo View":
           return i.findChild(QtGui.QTabWidget)
       elif str(i.objectName()) == "Python Console":
           return i.findChild(QtGui.QTabWidget)
   raise Exception ("No tab widget found")

mw = getMainWindow()
tab = getComboView(getMainWindow())
tab2=QtGui.QDialog()
tab.addTab(tab2,"A Special Tab")

#uic.loadUi("/myTaskPanelforTabs.ui",tab2)
tab2.show()
#tab.removeTab(2)

Enable or disable a window

from PySide import QtGui
mw=FreeCADGui.getMainWindow()
dws=mw.findChildren(QtGui.QDockWidget)

# objectName may be :
# "Report view"
# "Tree view"
# "Property view"
# "Selection view"
# "Combo View"
# "Python console"
# "draftToolbar"

for i in dws:
  if i.objectName() == "Report view":
    dw=i
    break

va=dw.toggleViewAction()
va.setChecked(True)        # True or False
dw.setVisible(True)        # True or False

Opening a custom webpage

import WebGui
WebGui.openBrowser("http://www.example.com")

Getting the HTML contents of an opened webpage

from PySide 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 :
  points=[]
  for obj in sel:
    points.append(obj.Shape.BoundBox.Center)

  for pt in points:
    # display of the coordinates in the report view
    Console.PrintMessage(str(pt.x)+"\r\n")
    Console.PrintMessage(str(pt.y)+"\r\n")
    Console.PrintMessage(str(pt.z)+"\r\n")

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

List all objects

# -*- coding: utf-8 -*-
import FreeCAD,Draft
# List all objects of the document
doc = FreeCAD.ActiveDocument
objs = FreeCAD.ActiveDocument.Objects
#App.Console.PrintMessage(str(objs) + "\n")
#App.Console.PrintMessage(str(len(FreeCAD.ActiveDocument.Objects)) + " Objects"  + "\n")

for obj in objs:
    a = obj.Name                                             # list the Name  of the object  (not modifiable)
    b = obj.Label                                            # list the Label of the object  (modifiable)
    try:
        c = obj.LabelText                                    # list the LabeText of the text (modifiable)
        App.Console.PrintMessage(str(a) +" "+ str(b) +" "+ str(c) + "\n") # Displays the Name the Label and the text
    except:
        App.Console.PrintMessage(str(a) +" "+ str(b) + "\n") # Displays the Name and the Label of the object

#doc.removeObject("Box") # Clears the designated object

List the dimensions of an object, given its name

for edge in FreeCAD.ActiveDocument.MyObjectName.Shape.Edges: # replace "MyObjectName" for list
    print edge.Length


Function resident with the mouse click action

Here with SelObserver on a object select

# -*- 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 setPreselection(self,doc,obj,sub):                # Preselection object
        App.Console.PrintMessage(str(sub)+ "\n")          # The part of the object name

    def addSelection(self,doc,obj,sub,pnt):               # Selection object
        App.Console.PrintMessage("addSelection"+ "\n")
        App.Console.PrintMessage(str(doc)+ "\n")          # Name of the document
        App.Console.PrintMessage(str(obj)+ "\n")          # Name of the object
        App.Console.PrintMessage(str(sub)+ "\n")          # The part of the object name
        App.Console.PrintMessage(str(pnt)+ "\n")          # Coordinates of the object
        App.Console.PrintMessage("______"+ "\n")

    def removeSelection(self,doc,obj,sub):                # Delete the selected object
        App.Console.PrintMessage("removeSelection"+ "\n")

    def setSelection(self,doc):                           # Selection in ComboView
        App.Console.PrintMessage("setSelection"+ "\n")

    def clearSelection(self,doc):                         # If click on the screen, clear the selection
        App.Console.PrintMessage("clearSelection"+ "\n")  # If click on another object, clear the previous object
s =SelObserver()
FreeCADGui.Selection.addObserver(s)                       # install the function mode resident
#FreeCADGui.Selection.removeObserver(s)                   # Uninstall the resident function

Other example with ViewObserver on a object select or view

App.newDocument()
v=Gui.activeDocument().activeView()
 
#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 __init__(self, view):
       self.view = view
   
   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")
           pnt = self.view.getPoint(pos)
           FreeCAD.Console.PrintMessage("World coordinates: " + str(pnt) + "\n")
           info = self.view.getObjectInfo(pos)
           FreeCAD.Console.PrintMessage("Object info: " + str(info) + "\n")

o = ViewObserver(v)
c = v.addEventCallback("SoMouseButtonEvent",o.logPosition)

Finding-selecting all elements below cursor

from pivy import coin
import FreeCADGui

def mouse_over_cb( event_callback):
    event = event_callback.getEvent()
    pos = event.getPosition().getValue()
    listObjects = FreeCADGui.ActiveDocument.ActiveView.getObjectsInfo((int(pos[0]),int(pos[1])))
    obj = []
    if listObjects:
        FreeCAD.Console.PrintMessage("\n *** Objects under mouse pointer ***")
        for o in listObjects:
            label = str(o["Object"])
            if not label in obj:
                obj.append(label)
        FreeCAD.Console.PrintMessage("\n"+str(obj))


view = FreeCADGui.ActiveDocument.ActiveView

mouse_over = view.addEventCallbackPivy( coin.SoLocation2Event.getClassTypeId(), mouse_over_cb )

# to remove Callback :
#view.removeEventCallbackPivy( coin.SoLocation2Event.getClassTypeId(), mouse_over)

####
#The easy way is probably to use FreeCAD's selection.
#FreeCADGui.ActiveDocument.ActiveView.getObjectsInfo(mouse_coords)

####
#you get that kind of result :
#'Document': 'Unnamed', 'Object': 'Box', 'Component': 'Face2', 'y': 8.604081153869629, 'x': 21.0, 'z': 8.553047180175781

####
#You can use this data to add your element to FreeCAD's selection :
#FreeCADGui.Selection.addSelection(FreeCAD.ActiveDocument.Box,'Face2',21.0,8.604081153869629,8.553047180175781)

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 center of mass and coordinates
# its faces and their center of mass
# its faces and their surfaces and coordinates
# 8/05/2014

import Draft,Part
def detail():
    sel = FreeCADGui.Selection.getSelection()   # Select an object
    if len(sel) != 0:                           # If there is a selection then
        Vertx=[]
        Edges=[]
        Faces=[]
        compt_V=0
        compt_E=0
        compt_F=0
        pas    =0
        perimetre = 0.0   
        EdgesLong = []

        # Displays the "Name" and the "Label" of the selection
        App.Console.PrintMessage("Selection > " + str(sel[0].Name) + "  " + str(sel[0].Label) +"\n"+"\n")

        for j in enumerate(sel[0].Shape.Edges):                                     # Search the "Edges" and their lengths
            compt_E+=1
            Edges.append("Edge%d" % (j[0]+1))
            EdgesLong.append(str(sel[0].Shape.Edges[compt_E-1].Length))
            perimetre += (sel[0].Shape.Edges[compt_E-1].Length)                     # calculates the perimeter

            # Displays the "Edge" and its length
            App.Console.PrintMessage("Edge"+str(compt_E)+" Length > "+str(sel[0].Shape.Edges[compt_E-1].Length)+"\n")

            # Displays the "Edge" and its center mass
            App.Console.PrintMessage("Edge"+str(compt_E)+" Center > "+str(sel[0].Shape.Edges[compt_E-1].CenterOfMass)+"\n")

            num = sel[0].Shape.Edges[compt_E-1].Vertexes[0]
            Vertx.append("X1: "+str(num.Point.x))
            Vertx.append("Y1: "+str(num.Point.y))
            Vertx.append("Z1: "+str(num.Point.z))
            # Displays the coordinates 1
            App.Console.PrintMessage("X1: "+str(num.Point[0])+" Y1: "+str(num.Point[1])+" Z1: "+str(num.Point[2])+"\n")

            try:
                num = sel[0].Shape.Edges[compt_E-1].Vertexes[1]
                Vertx.append("X2: "+str(num.Point.x))
                Vertx.append("Y2: "+str(num.Point.y))
                Vertx.append("Z2: "+str(num.Point.z))
            except:
                Vertx.append("-")
                Vertx.append("-")
                Vertx.append("-")
            # Displays the coordinates 2
            App.Console.PrintMessage("X2: "+str(num.Point[0])+" Y2: "+str(num.Point[1])+" Z2: "+str(num.Point[2])+"\n")

            App.Console.PrintMessage("\n")
        App.Console.PrintMessage("Perimeter of the form  : "+str(perimetre)+"\n") 

        App.Console.PrintMessage("\n")
        FacesSurf = []
        for j in enumerate(sel[0].Shape.Faces):                                      # Search the "Faces" and their surface
            compt_F+=1
            Faces.append("Face%d" % (j[0]+1))
            FacesSurf.append(str(sel[0].Shape.Faces[compt_F-1].Area))

            # Displays 'Face' and its surface
            App.Console.PrintMessage("Face"+str(compt_F)+" >  Surface "+str(sel[0].Shape.Faces[compt_F-1].Area)+"\n")

            # Displays 'Face' and its CenterOfMass
            App.Console.PrintMessage("Face"+str(compt_F)+" >  Center  "+str(sel[0].Shape.Faces[compt_F-1].CenterOfMass)+"\n")

            # Displays 'Face' and its Coordinates
            FacesCoor = []
            fco = 0
            for f0 in sel[0].Shape.Faces[compt_F-1].Vertexes:                        # Search the Vertexes of the face
                fco += 1
                FacesCoor.append("X"+str(fco)+": "+str(f0.Point.x))
                FacesCoor.append("Y"+str(fco)+": "+str(f0.Point.y))
                FacesCoor.append("Z"+str(fco)+": "+str(f0.Point.z))

            # Displays 'Face' and its Coordinates
            App.Console.PrintMessage("Face"+str(compt_F)+" >  Coordinate"+str(FacesCoor)+"\n")

            # Displays 'Face' and its Volume
            App.Console.PrintMessage("Face"+str(compt_F)+" >  Volume  "+str(sel[0].Shape.Faces[compt_F-1].Volume)+"\n")
            App.Console.PrintMessage("\n")

        # Displays the total surface of the form
        App.Console.PrintMessage("Surface of the form    : "+str(sel[0].Shape.Area)+"\n")

        # Displays the total Volume of the form
        App.Console.PrintMessage("Volume  of the form    : "+str(sel[0].Shape.Volume)+"\n")

detail()

List the PropertiesList

import FreeCADGui
from FreeCAD import Console
o = App.ActiveDocument.ActiveObject
op = o.PropertiesList
for p in op:
    Console.PrintMessage("Property: "+ str(p)+ " Value: " + str(o.getPropertyByName(p))+"\r\n")

Adding one Property "Comment"

import Draft
obj = FreeCADGui.Selection.getSelection()[0]
obj.addProperty("App::PropertyString","GComment","Draft","Font name").GComment = "Comment here"
App.activeDocument().recompute()

Search and data extraction

Examples of research and decoding information on an object.

Each section is independently and is separated by "############" can be copied directly into the Python console, or in a macro or use this macro. The description of the macro in the commentary.

Displaying it in the "View Report" window (View > Views > View report)

# -*- coding: utf-8 -*-
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
 
# Exemples de recherche et de decodage d'informations sur un objet
# Chaque section peut etre copiee directement dans la console Python ou dans une macro ou utilisez la macro tel quel
# Certaines commandes se repetent seul l'approche est differente
# L'affichage se fait dans la Vue rapport : Menu Affichage > Vues > Vue rapport
#
# Examples of research and decoding information on an object
# Each section can be copied directly into the Python console, or in a macro or uses this macro
# Certain commands as repeat alone approach is different
# Displayed on Report view : Menu View > Views > report view
#
# rev:30/08/2014:29/09/2014:17/09/2015
 
from FreeCAD import Base
import DraftVecUtils, Draft, Part
 
mydoc = FreeCAD.activeDocument().Name                                     # Name of active Document
App.Console.PrintMessage("Active docu    : "+(mydoc)+"\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
object_Label = sel[0].Label                                               # Label of the object (modifiable)
App.Console.PrintMessage("object_Label   : "+(object_Label)+"\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
App.Console.PrintMessage("sel            : "+str(sel[0])+"\n\n")          # sel[0] first object selected
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
object_Name  = sel[0].Name                                                # Name of the object (not modifiable)
App.Console.PrintMessage("object_Name    : "+str(object_Name)+"\n\n")
##################################################################################
 
try:
    SubElement = FreeCADGui.Selection.getSelectionEx()                    # sub element name with getSelectionEx()
    element_ = SubElement[0].SubElementNames[0]                           # name of 1 element selected
    App.Console.PrintMessage("elementSelec   : "+str(element_)+"\n\n")            
except:
    App.Console.PrintMessage("Oups"+"\n\n")            
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
App.Console.PrintMessage("sel            : "+str(sel[0])+"\n\n")          # sel[0] first object selected
##################################################################################
 
SubElement = FreeCADGui.Selection.getSelectionEx()                        # sub element name with getSelectionEx()
App.Console.PrintMessage("SubElement     : "+str(SubElement[0])+"\n\n")   # name of sub element
##################################################################################

SubElement = Gui.Selection.getSelectionEx()[0].SubObjects[0].Length       # sub element or element name with getSelectionEx()
App.Console.PrintMessage("SubElement length: "+str(length)+"\n")          # length
##################################################################################

sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
i = 0
for j in enumerate(sel[0].Shape.Edges):                                   # list all Edges
    i += 1
    App.Console.PrintMessage("Edges n : "+str(i)+"\n")
    a = sel[0].Shape.Edges[j[0]].Vertexes[0]
    App.Console.PrintMessage("X1             : "+str(a.Point.x)+"\n")     # coordinate XYZ first point
    App.Console.PrintMessage("Y1             : "+str(a.Point.y)+"\n")
    App.Console.PrintMessage("Z1             : "+str(a.Point.z)+"\n")
    try:
        a = sel[0].Shape.Edges[j[0]].Vertexes[1]
        App.Console.PrintMessage("X2             : "+str(a.Point.x)+"\n") # coordinate XYZ second point
        App.Console.PrintMessage("Y2             : "+str(a.Point.y)+"\n")
        App.Console.PrintMessage("Z2             : "+str(a.Point.z)+"\n")
    except:
        App.Console.PrintMessage("Oups"+"\n")    
App.Console.PrintMessage("\n")    
##################################################################################
 
try:
    SubElement = FreeCADGui.Selection.getSelectionEx()                                        # sub element name with getSelectionEx()
    subElementName = Gui.Selection.getSelectionEx()[0].SubElementNames[0]                     # sub element name with getSelectionEx()
    App.Console.PrintMessage("subElementName : "+str(subElementName)+"\n")
    
    subObjectLength = Gui.Selection.getSelectionEx()[0].SubObjects[0].Length                  # sub element Length
    App.Console.PrintMessage("subObjectLength: "+str(subObjectLength)+"\n\n")
    
    subObjectX1 = Gui.Selection.getSelectionEx()[0].SubObjects[0].Vertexes[0].Point.x         # sub element coordinate X1
    App.Console.PrintMessage("subObject_X1   : "+str(subObjectX1)+"\n")
    subObjectY1 = Gui.Selection.getSelectionEx()[0].SubObjects[0].Vertexes[0].Point.y         # sub element coordinate Y1
    App.Console.PrintMessage("subObject_Y1   : "+str(subObjectY1)+"\n")
    subObjectZ1 = Gui.Selection.getSelectionEx()[0].SubObjects[0].Vertexes[0].Point.z         # sub element coordinate Z1
    App.Console.PrintMessage("subObject_Z1   : "+str(subObjectZ1)+"\n\n")

    try:
        subObjectX2 = Gui.Selection.getSelectionEx()[0].SubObjects[0].Vertexes[1].Point.x     # sub element coordinate X2
        App.Console.PrintMessage("subObject_X2   : "+str(subObjectX2)+"\n")
        subObjectY2 = Gui.Selection.getSelectionEx()[0].SubObjects[0].Vertexes[1].Point.y     # sub element coordinate Y2
        App.Console.PrintMessage("subObject_Y2   : "+str(subObjectY2)+"\n")
        subObjectZ2 = Gui.Selection.getSelectionEx()[0].SubObjects[0].Vertexes[1].Point.z     # sub element coordinate Z2
        App.Console.PrintMessage("subObject_Z2   : "+str(subObjectZ2)+"\n\n")
    except:
        App.Console.PrintMessage("Oups"+"\n\n")            

    subObjectBoundBox = Gui.Selection.getSelectionEx()[0].SubObjects[0].BoundBox              # sub element BoundBox coordinates
    App.Console.PrintMessage("subObjectBBox  : "+str(subObjectBoundBox)+"\n")
    
    subObjectBoundBoxCenter = Gui.Selection.getSelectionEx()[0].SubObjects[0].BoundBox.Center # sub element BoundBoxCenter
    App.Console.PrintMessage("subObjectBBoxCe: "+str(subObjectBoundBoxCenter)+"\n")
    
    surfaceFace = Gui.Selection.getSelectionEx()[0].SubObjects[0].Area                        # Area of the face selected
    App.Console.PrintMessage("surfaceFace    : "+str(surfaceFace)+"\n\n")
except:
    App.Console.PrintMessage("Oups"+"\n\n")            
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
surface = sel[0].Shape.Area                                               # Area object complete
App.Console.PrintMessage("surfaceObjet   : "+str(surface)+"\n\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
CenterOfMass = sel[0].Shape.CenterOfMass                                  # Center of Mass of the object
App.Console.PrintMessage("CenterOfMass   : "+str(CenterOfMass)+"\n")
App.Console.PrintMessage("CenterOfMassX  : "+str(CenterOfMass[0])+"\n")   # coordinates [0]=X [1]=Y [2]=Z
App.Console.PrintMessage("CenterOfMassY  : "+str(CenterOfMass[1])+"\n")
App.Console.PrintMessage("CenterOfMassZ  : "+str(CenterOfMass[2])+"\n\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
for j in enumerate(sel[0].Shape.Faces):                                   # List alles faces of the object
    App.Console.PrintMessage("Face           : "+str("Face%d" % (j[0]+1))+"\n")
App.Console.PrintMessage("\n\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
volume_ = sel[0].Shape.Volume                                             # Volume of the object
App.Console.PrintMessage("volume_        : "+str(volume_)+"\n\n")
##################################################################################
 
objs = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()

if len(objs) >= 1:
    if hasattr(objs[0], "Shape"):
        s = objs[0].Shape
    elif hasattr(objs[0], "Mesh"):      # upgrade with wmayer thanks #http://forum.freecadweb.org/viewtopic.php?f=13&t=22331
        s = objs[0].Mesh
    elif hasattr(objs[0], "Points"):
        s = objs[0].Points

#sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
#boundBox_= sel[0].Shape.BoundBox                                          # BoundBox of the object
boundBox_= s.BoundBox                                                      # BoundBox of the object
App.Console.PrintMessage("boundBox_      : "+str(boundBox_)+"\n")
 
boundBoxLX  = boundBox_.XLength                                           # Length x boundBox rectangle
boundBoxLY  = boundBox_.YLength                                           # Length y boundBox rectangle
boundBoxLZ  = boundBox_.ZLength                                           # Length z boundBox rectangle
boundBoxDiag= boundBox_.DiagonalLength                                    # Diagonal Length boundBox rectangle

App.Console.PrintMessage("boundBoxLX     : "+str(boundBoxLX)+"\n")
App.Console.PrintMessage("boundBoxLY     : "+str(boundBoxLY)+"\n")
App.Console.PrintMessage("boundBoxLZ     : "+str(boundBoxLZ)+"\n")
App.Console.PrintMessage("boundBoxDiag   : "+str(boundBoxDiag)+"\n\n")

##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
pl = sel[0].Shape.Placement                                               # Placement Vector XYZ and Yaw-Pitch-Roll
App.Console.PrintMessage("Placement      : "+str(pl)+"\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
pl = sel[0].Shape.Placement.Base                                          # Placement Vector XYZ
App.Console.PrintMessage("PlacementBase  : "+str(pl)+"\n\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
oripl_X = sel[0].Placement.Base[0]                                        # decode Placement X
oripl_Y = sel[0].Placement.Base[1]                                        # decode Placement Y
oripl_Z = sel[0].Placement.Base[2]                                        # decode Placement Z
 
App.Console.PrintMessage("oripl_X        : "+str(oripl_X)+"\n")
App.Console.PrintMessage("oripl_Y        : "+str(oripl_Y)+"\n")
App.Console.PrintMessage("oripl_Z        : "+str(oripl_Z)+"\n\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
rotation = sel[0].Placement.Rotation                                      # decode Placement Rotation
App.Console.PrintMessage("rotation              : "+str(rotation)+"\n\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
pl = sel[0].Shape.Placement.Rotation                                      # decode Placement Rotation other method
App.Console.PrintMessage("Placement Rot         : "+str(pl)+"\n\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
pl = sel[0].Shape.Placement.Rotation.Angle                                # decode Placement Rotation Angle
App.Console.PrintMessage("Placement Rot Angle   : "+str(pl)+"\n\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
Rot_0 = sel[0].Placement.Rotation.Q[0]                                    # decode Placement Rotation Q
App.Console.PrintMessage("Rot_0         : "+str(Rot_0)+ " rad ,  "+str(180 * Rot_0 / 3.1416)+" deg "+"\n")
 
Rot_1 = sel[0].Placement.Rotation.Q[1]                                    # decode Placement Rotation 1
App.Console.PrintMessage("Rot_1         : "+str(Rot_1)+ " rad ,  "+str(180 * Rot_1 / 3.1416)+" deg "+"\n")
 
Rot_2 = sel[0].Placement.Rotation.Q[2]                                    # decode Placement Rotation 2
App.Console.PrintMessage("Rot_2         : "+str(Rot_2)+ " rad ,  "+str(180 * Rot_2 / 3.1416)+" deg "+"\n")
 
Rot_3 = sel[0].Placement.Rotation.Q[3]                                    # decode Placement Rotation 3
App.Console.PrintMessage("Rot_3         : "+str(Rot_3)+"\n\n")
##################################################################################
 
sel = FreeCADGui.Selection.getSelection()                                 # select object with getSelection()
Yaw   = sel[0].Shape.Placement.Rotation.toEuler()[0]                      # decode angle Euler Yaw (Z)
App.Console.PrintMessage("Yaw            : "+str(Yaw)+"\n")
Pitch = sel[0].Shape.Placement.Rotation.toEuler()[1]                      # decode angle Euler Pitch (Y)
App.Console.PrintMessage("Pitch          : "+str(Pitch)+"\n")
Roll  = sel[0].Shape.Placement.Rotation.toEuler()[2]                      # decode angle Euler Roll (X)
App.Console.PrintMessage("Roll           : "+str(Roll)+"\n\n")
##################################################################################

import DraftGeomUtils
sel = FreeCADGui.Selection.getSelection()
vecteur = DraftGeomUtils.findMidpoint(sel[0].Shape.Edges[0])              # find Midpoint
App.Console.PrintMessage(vecteur)
Draft.makePoint(vecteur)
##################################################################################

Manual search of an element with label

# Extract the coordinate X,Y,Z and Angle giving the label 
App.Console.PrintMessage("Base.x       : "+str(FreeCAD.ActiveDocument.getObjectsByLabel("Cylindre")[0].Placement.Base.x)+"\n")
App.Console.PrintMessage("Base.y       : "+str(FreeCAD.ActiveDocument.getObjectsByLabel("Cylindre")[0].Placement.Base.y)+"\n")
App.Console.PrintMessage("Base.z       : "+str(FreeCAD.ActiveDocument.getObjectsByLabel("Cylindre")[0].Placement.Base.z)+"\n")
App.Console.PrintMessage("Base.Angle   : "+str(FreeCAD.ActiveDocument.getObjectsByLabel("Cylindre")[0].Placement.Rotation.Angle)+"\n\n")
##################################################################################

PS: Usually the angles are given in Radian to convert :

  1. angle in Degrees to Radians :
    • Angle in radian = pi * (angle in degree) / 180
    • Angle in radian = math.radians(angle in degree)
  2. angle in Radians to Degrees :
    • Angle in degree = 180 * (angle in radian) / pi
    • Angle in degree = math.degrees(angle in radian)

Cartesian coordinates

This code displays the Cartesian coordinates of the selected item.

Change the value of "numberOfPoints" if you want a different number of points (precision)

numberOfPoints = 100                                                         # Decomposition number (or precision you can change)
selectedEdge = FreeCADGui.Selection.getSelectionEx()[0].SubObjects[0].copy() # select one element
points  = selectedEdge.discretize(numberOfPoints)                            # discretize the element
i=0
for p in points:                                                             # list and display the coordinates
    i+=1
    print i, " X", p.x, " Y", p.y, " Z", p.z

Other method display on "Int" and "Float"

import Part
from FreeCAD import Base

c=Part.makeCylinder(2,10)        # create the circle
Part.show(c)                     # display the shape

# slice accepts two arguments:
#+ the normal of the cross section plane
#+ the distance from the origin to the cross section plane. Here you have to find a value so that the plane intersects your object
s=c.slice(Base.Vector(0,1,0),0)  # 

# here the result is a single wire
# depending on the source object this can be several wires
s=s[0]

# if you only need the vertexes of the shape you can use
v=[]
for i in s.Vertexes:
    v.append(i.Point)

# but you can also sub-sample the section to have a certain number of points (int) ...
p1=s.discretize(20)
ii=0
for i in p1:
    ii+=1
    print i                                              # Vector()
    print ii, ": X:", i.x, " Y:", i.y, " Z:", i.z        # Vector decode
Draft.makeWire(p1,closed=False,face=False,support=None)  # to see the difference accuracy (20)

## uncomment to use
#import Draft
#Draft.downgrade(App.ActiveDocument.ActiveObject,delete=True)  # first transform the DWire in Wire         "downgrade"
#Draft.downgrade(App.ActiveDocument.ActiveObject,delete=True)  # second split the Wire in single objects   "downgrade"
#
##Draft.upgrade(FreeCADGui.Selection.getSelection(),delete=True) # to attach lines contiguous SELECTED use "upgrade"


# ... or define a sampling distance (float)
p2=s.discretize(0.5)
ii=0
for i in p2:
    ii+=1
    print i                                              # Vector()
    print ii, ": X:", i.x, " Y:", i.y, " Z:", i.z        # Vector decode 
Draft.makeWire(p2,closed=False,face=False,support=None)  # to see the difference accuracy (0.5)

## uncomment to use
#import Draft
#Draft.downgrade(App.ActiveDocument.ActiveObject,delete=True)  # first transform the DWire in Wire         "downgrade"
#Draft.downgrade(App.ActiveDocument.ActiveObject,delete=True)  # second split the Wire in single objects   "downgrade"
#
##Draft.upgrade(FreeCADGui.Selection.getSelection(),delete=True) # to attach lines contiguous SELECTED use "upgrade"

Select all objects in the document

import FreeCAD
for obj in FreeCAD.ActiveDocument.Objects:
    print obj.Name                                # display the object Name
    objName = obj.Name
    obj = App.ActiveDocument.getObject(objName)
    Gui.Selection.addSelection(obj)               # select the object

Selecting a face of an object

# select one face of the object
import FreeCAD, Draft
App=FreeCAD
nameObject = "Box"                             # objet
faceSelect = "Face3"                           # face to selection
loch=App.ActiveDocument.getObject(nameObject)  # objet
Gui.Selection.clearSelection()                 # clear all selection
Gui.Selection.addSelection(loch,faceSelect)    # select the face specified
s = Gui.Selection.getSelectionEx()
#Draft.makeFacebinder(s)                       #

Create one object to the position of the Camera

# create one object of the position to camera with "getCameraOrientation()"
# the object is still facing the screen
import Draft

plan = FreeCADGui.ActiveDocument.ActiveView.getCameraOrientation()
plan = str(plan)
###### extract data
a    = ""
for i in plan:
    if i in ("0123456789e.- "):
        a+=i
a = a.strip(" ")
a = a.split(" ")
####### extract data

#print a
#print a[0]
#print a[1]
#print a[2]
#print a[3]

xP = float(a[0])
yP = float(a[1])
zP = float(a[2])
qP = float(a[3])

pl = FreeCAD.Placement()
pl.Rotation.Q = (xP,yP,zP,qP)         # rotation of object
pl.Base = FreeCAD.Vector(0.0,0.0,0.0) # here coordinates XYZ of Object
rec = Draft.makeRectangle(length=10.0,height=10.0,placement=pl,face=False,support=None) # create rectangle
#rec = Draft.makeCircle(radius=5,placement=pl,face=False,support=None)                   # create circle
print rec.Name

here same code simplified

import Draft
pl = FreeCAD.Placement()
pl.Rotation = FreeCADGui.ActiveDocument.ActiveView.getCameraOrientation()
pl.Base = FreeCAD.Vector(0.0,0.0,0.0)
rec = Draft.makeRectangle(length=10.0,height=10.0,placement=pl,face=False,support=None)

Find normal vector on the surface

This example show how to find normal vector on the surface by find the u,v parameters of one point on the surface and use u,v parameters to find normal vector

def normal(self):
   ss=FreeCADGui.Selection.getSelectionEx()[0].SubObjects[0].copy()#SubObjects[0] is the edge list
   points  = ss.discretize(3.0)#points on the surface edge, 
             #this example just use points on the edge for example. 
             #However point is not necessary on the edge, it can be anywhere on the surface. 
   face=FreeCADGui.Selection.getSelectionEx()[0].SubObjects[1]
   for pp in points:
      pt=FreeCAD.Base.Vector(pp.x,pp.y,pp.z)#a point on the surface edge
      uv=face.Surface.parameter(pt)# find the surface u,v parameter of a point on the surface edge
      u=uv[0]
      v=uv[1]
      normal=face.normalAt(u,v)#use u,v to find normal vector
      print normal
      line=Part.makeLine((pp.x,pp.y,pp.z), (normal.x,normal.y,normal.z))
      Part.show(line)

Read And write one Expression

import Draft
doc = FreeCAD.ActiveDocument

pl=FreeCAD.Placement()
pl.Rotation.Q=(0.0,-0.0,-0.0,1.0)
pl.Base=FreeCAD.Vector(0.0,0.0,0.0)
obj = Draft.makeCircle(radius=1.0,placement=pl,face=False,support=None)    # create circle

print obj.PropertiesList                                                   # properties disponible in the obj

doc.getObject(obj.Name).setExpression('Radius', u'2mm')                    # modify the radius
doc.getObject(obj.Name).setExpression('Placement.Base.x', u'10mm')         # modify the placement 
doc.getObject(obj.Name).setExpression('FirstAngle', u'90')                 # modify the first angle
doc.recompute()

expressions = obj.ExpressionEngine                                         # read the expression list
print expressions

for i in expressions:                                                      # list and separate the data expression
    print i[0]," = ",i[1]


Get the normal vector of a suface from a STL file

def getNormal(cb):
    if cb.getEvent().getState() == coin.SoButtonEvent.UP:
        pp = cb.getPickedPoint()
        if pp:
            vec = pp.getNormal().getValue()
            index = coin.cast(pp.getDetail(), "SoFaceDetail").getFaceIndex()
            print ("Normal: {}, Face index: {}".format(str(vec), index))

from pivy import coin
meth=Gui.ActiveDocument.ActiveView.addEventCallbackPivy(coin.SoMouseButtonEvent.getClassTypeId(), getNormal)

you are done then run for quit:

Gui.ActiveDocument.ActiveView.removeEventCallbackPivy(coin.SoMouseButtonEvent.getClassTypeId(), meth)