Förutom standard objekttyper som annoteringar, nät och delobjekt, så erbjuder FreeCAD också den fantastiska möjligheten att bygga 100% python-skriptade objekt, som kallas för Python Funktioner. dessa objekt kommer att bete sig exakt som alla andra FreeCAD objekt, de kan sparas i ett dokument och öppnas av en annan FreeCAD installation, eftersom den python kod som definierar objektet även sparas i dokumentet.
One particularity must be understood, those objects are saved in FreeCAD FcStd files with python's json module. That module turns a python object as a string, allowing it to be added to the saved file. On load, the json module uses that string to recreate the original object, provided it has access to the source code that created the object. This means that if you save such a custom object and open it on a machine where the python code that generated the object is not present, the object won't be recreated. If you distribute such objects to others, you will need to distribute the python script that created it together.
Python Funktioner följer samma regler som alla FreeCAD funktioner: de är separerade i App och GUI delar. App delen, Dokumentobjektet, definierar vårt objekts geometri , medan dess gränssnittsdel, Visaobjektet, definierar hur objektet kommer att ritas på skärmen. VisaObjektet, är som alla andra FreeCAD funktioner, endast tillgängligt när du kör FreeCAD i dess eget gränssnitt. Det finns flera egenskaper och metoder tillgängliga för att bygga ditt objekt. Egenskaperna måste vara en av de fördefinierade egenskapstyperna som FreeCAD erbjuder, och kommer att visas i egenskapsfönstret, så de kan redigeras av användaren. på detta sätt så är Python Funktionsobjekt totalt parametrisk. Du kan definiera egenskaper för objektet och dess Visaobjekt separat.
Hint: In former versions we used Python's cPickle module. However, this module executes arbitrary code and thus causes a security problem. Thus, we moved to Python's json module.
The following sample can be found in the src/Mod/TemplatePyMod/FeaturePython.py file, together with several other examples:
'''Examples for a feature class and its view provider.'''
import FreeCAD, FreeCADGui
from pivy import coin
class Box:
def __init__(self, obj):
'''Add some custom properties to our box feature'''
obj.addProperty("App::PropertyLength","Length","Box","Length of the box").Length=1.0
obj.addProperty("App::PropertyLength","Width","Box","Width of the box").Width=1.0
obj.addProperty("App::PropertyLength","Height","Box", "Height of the box").Height=1.0
obj.Proxy = self
def onChanged(self, fp, prop):
'''Do something when a property has changed'''
FreeCAD.Console.PrintMessage("Change property: " + str(prop) + "\n")
def execute(self, fp):
'''Do something when doing a recomputation, this method is mandatory'''
FreeCAD.Console.PrintMessage("Recompute Python Box feature\n")
class ViewProviderBox:
def __init__(self, obj):
'''Set this object to the proxy object of the actual view provider'''
obj.addProperty("App::PropertyColor","Color","Box","Color of the box").Color=(1.0,0.0,0.0)
obj.Proxy = self
def attach(self, obj):
'''Setup the scene sub-graph of the view provider, this method is mandatory'''
self.shaded = coin.SoGroup()
self.wireframe = coin.SoGroup()
self.scale = coin.SoScale()
self.color = coin.SoBaseColor()
data=coin.SoCube()
self.shaded.addChild(self.scale)
self.shaded.addChild(self.color)
self.shaded.addChild(data)
obj.addDisplayMode(self.shaded,"Shaded");
style=coin.SoDrawStyle()
style.style = coin.SoDrawStyle.LINES
self.wireframe.addChild(style)
self.wireframe.addChild(self.scale)
self.wireframe.addChild(self.color)
self.wireframe.addChild(data)
obj.addDisplayMode(self.wireframe,"Wireframe");
self.onChanged(obj,"Color")
def updateData(self, fp, prop):
'''If a property of the handled feature has changed we have the chance to handle this here'''
# fp is the handled feature, prop is the name of the property that has changed
l = fp.getPropertyByName("Length")
w = fp.getPropertyByName("Width")
h = fp.getPropertyByName("Height")
self.scale.scaleFactor.setValue(float(l),float(w),float(h))
pass
def getDisplayModes(self,obj):
'''Return a list of display modes.'''
modes=[]
modes.append("Shaded")
modes.append("Wireframe")
return modes
def getDefaultDisplayMode(self):
'''Return the name of the default display mode. It must be defined in getDisplayModes.'''
return "Shaded"
def setDisplayMode(self,mode):
'''Map the display mode defined in attach with those defined in getDisplayModes.\
Since they have the same names nothing needs to be done. This method is optional'''
return mode
def onChanged(self, vp, prop):
'''Here we can do something when a single property got changed'''
FreeCAD.Console.PrintMessage("Change property: " + str(prop) + "\n")
if prop == "Color":
c = vp.getPropertyByName("Color")
self.color.rgb.setValue(c[0],c[1],c[2])
def getIcon(self):
'''Return the icon in XPM format which will appear in the tree view. This method is\
optional and if not defined a default icon is shown.'''
return """
/* XPM */
static const char * ViewProviderBox_xpm[] = {
"16 16 6 1",
" c None",
". c #141010",
"+ c #615BD2",
"@ c #C39D55",
"# c #000000",
"$ c #57C355",
" ........",
" ......++..+..",
" .@@@@.++..++.",
" .@@@@.++..++.",
" .@@ .++++++.",
" ..@@ .++..++.",
"###@@@@ .++..++.",
"##$.@@$#.++++++.",
"#$#$.$$$........",
"#$$####### ",
"#$$#$$$$$# ",
"#$$#$$$$$# ",
"#$$#$$$$$# ",
" #$#$$$$$# ",
" ##$$$$$# ",
" ####### "};
"""
def __getstate__(self):
'''When saving the document this object gets stored using Python's json module.\
Since we have some un-serializable parts here -- the Coin stuff -- we must define this method\
to return a tuple of all serializable objects or None.'''
return None
def __setstate__(self,state):
'''When restoring the serialized object from document we have the chance to set some internals here.\
Since no data were serialized nothing needs to be done here.'''
return None
def makeBox():
FreeCAD.newDocument()
a=FreeCAD.ActiveDocument.addObject("App::FeaturePython","Box")
Box(a)
ViewProviderBox(a.ViewObject)
makeBox()
Egenskaper är PythonFunktion objektens sanna byggstenar. Genom dem, så kan användaren interagera och ändra objektet. Efter att ett nytt PythonFunktion objekt har skapats i ditt dokument ( a=FreeCAD.ActiveDocument.addObject("App::FeaturePython","Box") ), så kan du få en lista på de tillgängliga egenskaperna genom att skriva:
obj.supportedProperties()
Du kommer att få en lista på tillgängliga egenskaper:
App::PropertyBool App::PropertyBoolList App::PropertyFloat App::PropertyFloatList App::PropertyFloatConstraint App::PropertyQuantity App::PropertyQuantityConstraint App::PropertyAngle App::PropertyDistance App::PropertyLength App::PropertySpeed App::PropertyAcceleration App::PropertyForce App::PropertyPressure App::PropertyInteger App::PropertyIntegerConstraint App::PropertyPercent App::PropertyEnumeration App::PropertyIntegerList App::PropertyIntegerSet App::PropertyMap App::PropertyString App::PropertyUUID App::PropertyFont App::PropertyStringList App::PropertyLink App::PropertyLinkSub App::PropertyLinkList App::PropertyLinkSubList App::PropertyMatrix App::PropertyVector App::PropertyVectorList App::PropertyPlacement App::PropertyPlacementLink App::PropertyColor App::PropertyColorList App::PropertyMaterial App::PropertyPath App::PropertyFile App::PropertyFileIncluded App::PropertyPythonObject Part::PropertyPartShape Part::PropertyGeometryList Part::PropertyShapeHistory Part::PropertyFilletEdges Sketcher::PropertyConstraintList
När du adderar egenskaper till dina anpassade objekt, var uppmärksam på detta:
By default the properties can be updated. It is possible to make the properties read-only, for instance in the case one wants to show the result of a method. It is also possible to hide the property. The property type can be set using
obj.setEditorMode("MyPropertyName", mode)
where mode is a short int that can be set to:
0 -- default mode, read and write 1 -- read-only 2 -- hidden
The EditorModes are not set at FreeCAD file reload. This could to be done by the __setstate__ function. See http://forum.freecadweb.org/viewtopic.php?f=18&t=13460&start=10#p108072. By using the setEditorMode the properties are only read only in PropertyEditor. They could still be changed from python. To really make them read only the setting has to be passed directly inside the addProperty function. See http://forum.freecadweb.org/viewtopic.php?f=18&t=13460&start=20#p109709 for an example.
Detta exempel använder sig av Del Modulen för att skapa en oktahedron, sedan skapas dess coin representation med pivy.
Det första är själva Dokument objektet:
import FreeCAD, FreeCADGui, Part
import pivy
from pivy import coin
class Octahedron:
def __init__(self, obj):
"Add some custom properties to our box feature"
obj.addProperty("App::PropertyLength","Length","Octahedron","Length of the octahedron").Length=1.0
obj.addProperty("App::PropertyLength","Width","Octahedron","Width of the octahedron").Width=1.0
obj.addProperty("App::PropertyLength","Height","Octahedron", "Height of the octahedron").Height=1.0
obj.addProperty("Part::PropertyPartShape","Shape","Octahedron", "Shape of the octahedron")
obj.Proxy = self
def execute(self, fp):
# Define six vetices for the shape
v1 = FreeCAD.Vector(0,0,0)
v2 = FreeCAD.Vector(fp.Length,0,0)
v3 = FreeCAD.Vector(0,fp.Width,0)
v4 = FreeCAD.Vector(fp.Length,fp.Width,0)
v5 = FreeCAD.Vector(fp.Length/2,fp.Width/2,fp.Height/2)
v6 = FreeCAD.Vector(fp.Length/2,fp.Width/2,-fp.Height/2)
# Make the wires/faces
f1 = self.make_face(v1,v2,v5)
f2 = self.make_face(v2,v4,v5)
f3 = self.make_face(v4,v3,v5)
f4 = self.make_face(v3,v1,v5)
f5 = self.make_face(v2,v1,v6)
f6 = self.make_face(v4,v2,v6)
f7 = self.make_face(v3,v4,v6)
f8 = self.make_face(v1,v3,v6)
shell=Part.makeShell([f1,f2,f3,f4,f5,f6,f7,f8])
solid=Part.makeSolid(shell)
fp.Shape = solid
# helper mehod to create the faces
def make_face(self,v1,v2,v3):
wire = Part.makePolygon([v1,v2,v3,v1])
face = Part.Face(wire)
return face
Sedan så har vi visarobjektet, ansvarigt för att visa objektet i 3D scenen:
class ViewProviderOctahedron:
def __init__(self, obj):
"Set this object to the proxy object of the actual view provider"
obj.addProperty("App::PropertyColor","Color","Octahedron","Color of the octahedron").Color=(1.0,0.0,0.0)
obj.Proxy = self
def attach(self, obj):
"Setup the scene sub-graph of the view provider, this method is mandatory"
self.shaded = coin.SoGroup()
self.wireframe = coin.SoGroup()
self.scale = coin.SoScale()
self.color = coin.SoBaseColor()
self.data=coin.SoCoordinate3()
self.face=coin.SoIndexedLineSet()
self.shaded.addChild(self.scale)
self.shaded.addChild(self.color)
self.shaded.addChild(self.data)
self.shaded.addChild(self.face)
obj.addDisplayMode(self.shaded,"Shaded");
style=coin.SoDrawStyle()
style.style = coin.SoDrawStyle.LINES
self.wireframe.addChild(style)
self.wireframe.addChild(self.scale)
self.wireframe.addChild(self.color)
self.wireframe.addChild(self.data)
self.wireframe.addChild(self.face)
obj.addDisplayMode(self.wireframe,"Wireframe");
self.onChanged(obj,"Color")
def updateData(self, fp, prop):
"If a property of the handled feature has changed we have the chance to handle this here"
# fp is the handled feature, prop is the name of the property that has changed
if prop == "Shape":
s = fp.getPropertyByName("Shape")
self.data.point.setNum(6)
cnt=0
for i in s.Vertexes:
self.data.point.set1Value(cnt,i.X,i.Y,i.Z)
cnt=cnt+1
self.face.coordIndex.set1Value(0,0)
self.face.coordIndex.set1Value(1,1)
self.face.coordIndex.set1Value(2,2)
self.face.coordIndex.set1Value(3,-1)
self.face.coordIndex.set1Value(4,1)
self.face.coordIndex.set1Value(5,3)
self.face.coordIndex.set1Value(6,2)
self.face.coordIndex.set1Value(7,-1)
self.face.coordIndex.set1Value(8,3)
self.face.coordIndex.set1Value(9,4)
self.face.coordIndex.set1Value(10,2)
self.face.coordIndex.set1Value(11,-1)
self.face.coordIndex.set1Value(12,4)
self.face.coordIndex.set1Value(13,0)
self.face.coordIndex.set1Value(14,2)
self.face.coordIndex.set1Value(15,-1)
self.face.coordIndex.set1Value(16,1)
self.face.coordIndex.set1Value(17,0)
self.face.coordIndex.set1Value(18,5)
self.face.coordIndex.set1Value(19,-1)
self.face.coordIndex.set1Value(20,3)
self.face.coordIndex.set1Value(21,1)
self.face.coordIndex.set1Value(22,5)
self.face.coordIndex.set1Value(23,-1)
self.face.coordIndex.set1Value(24,4)
self.face.coordIndex.set1Value(25,3)
self.face.coordIndex.set1Value(26,5)
self.face.coordIndex.set1Value(27,-1)
self.face.coordIndex.set1Value(28,0)
self.face.coordIndex.set1Value(29,4)
self.face.coordIndex.set1Value(30,5)
self.face.coordIndex.set1Value(31,-1)
def getDisplayModes(self,obj):
"Return a list of display modes."
modes=[]
modes.append("Shaded")
modes.append("Wireframe")
return modes
def getDefaultDisplayMode(self):
"Return the name of the default display mode. It must be defined in getDisplayModes."
return "Shaded"
def setDisplayMode(self,mode):
return mode
def onChanged(self, vp, prop):
"Here we can do something when a single property got changed"
FreeCAD.Console.PrintMessage("Change property: " + str(prop) + "\n")
if prop == "Color":
c = vp.getPropertyByName("Color")
self.color.rgb.setValue(c[0],c[1],c[2])
def getIcon(self):
return """
/* XPM */
static const char * ViewProviderBox_xpm[] = {
"16 16 6 1",
" c None",
". c #141010",
"+ c #615BD2",
"@ c #C39D55",
"# c #000000",
"$ c #57C355",
" ........",
" ......++..+..",
" .@@@@.++..++.",
" .@@@@.++..++.",
" .@@ .++++++.",
" ..@@ .++..++.",
"###@@@@ .++..++.",
"##$.@@$#.++++++.",
"#$#$.$$$........",
"#$$####### ",
"#$$#$$$$$# ",
"#$$#$$$$$# ",
"#$$#$$$$$# ",
" #$#$$$$$# ",
" ##$$$$$# ",
" ####### "};
"""
def __getstate__(self):
return None
def __setstate__(self,state):
return None
Slutligen, när vårt objekt och dess visningsobjekt är definierade, så behöver vi bara anropa dem:
FreeCAD.newDocument()
a=FreeCAD.ActiveDocument.addObject("App::FeaturePython","Octahedron")
Octahedron(a)
ViewProviderOctahedron(a.ViewObject)
Om du vill göra ditt objekt valbart, eller åtminstone en del av den, genom att klicka på den i vyn, så måste du inkludera dess geometri inuti en SoFCSelection nod. Om ditt objekt har en komplex representation, med widgetar, annoteringar, etc, så kanske du bara vill inkludera en del av den i en SoFCSelection. Allt som är en SoFCSelection skannas konstant av FreeCAD för att detektera val/förval, så det är vettigt att inte försöka överbelasta den med onödig skanning. Detta är vad du skulle göra för att inkludera en self.face från det ovan visade exemplet:
selectionNode = coin.SoType.fromName("SoFCSelection").createInstance()
selectionNode.documentName.setValue(FreeCAD.ActiveDocument.Name)
selectionNode.objectName.setValue(obj.Object.Name) # here obj is the ViewObject, we need its associated App Object
selectionNode.subElementName.setValue("Face")
selectNode.addChild(self.face)
...
self.shaded.addChild(selectionNode)
self.wireframe.addChild(selectionNode)
Du skapar en SoFCSelection nod, sedan lägger du till dina geometrinoder till den, sedan lägger du till den till din huvudnod, istället för att lägga till dina geometrinoder direkt.
Om ditt parametriska objektbara resulterar i en form, så behöver du inte använda ett visarobjekt. Formen kommer att visas med hjälp av FreeCAD's standard form representation:
import FreeCAD as App
import FreeCADGui
import FreeCAD
import Part
class Line:
def __init__(self, obj):
'''"App two point properties" '''
obj.addProperty("App::PropertyVector","p1","Line","Start point")
obj.addProperty("App::PropertyVector","p2","Line","End point").p2=FreeCAD.Vector(1,0,0)
obj.Proxy = self
def execute(self, fp):
'''"Print a short message when doing a recomputation, this method is mandatory" '''
fp.Shape = Part.makeLine(fp.p1,fp.p2)
a=FreeCAD.ActiveDocument.addObject("Part::FeaturePython","Line")
Line(a)
a.ViewObject.Proxy=0 # just set it to something different from None (this assignment is needed to run an internal notification)
FreeCAD.ActiveDocument.recompute()
Same code with use ViewProviderLine
import FreeCAD as App
import FreeCADGui
import FreeCAD
import Part
class Line:
def __init__(self, obj):
'''"App two point properties" '''
obj.addProperty("App::PropertyVector","p1","Line","Start point")
obj.addProperty("App::PropertyVector","p2","Line","End point").p2=FreeCAD.Vector(100,0,0)
obj.Proxy = self
def execute(self, fp):
'''"Print a short message when doing a recomputation, this method is mandatory" '''
fp.Shape = Part.makeLine(fp.p1,fp.p2)
class ViewProviderLine:
def __init__(self, obj):
''' Set this object to the proxy object of the actual view provider '''
obj.Proxy = self
def getDefaultDisplayMode(self):
''' Return the name of the default display mode. It must be defined in getDisplayModes. '''
return "Flat Lines"
a=FreeCAD.ActiveDocument.addObject("Part::FeaturePython","Line")
Line(a)
ViewProviderLine(a.ViewObject)
App.ActiveDocument.recompute()
There are a few very interesting forum threads about scripted objects:
- http://forum.freecadweb.org/viewtopic.php?f=22&t=13740
- http://forum.freecadweb.org/viewtopic.php?t=12139
- https://forum.freecadweb.org/viewtopic.php?f=18&t=13460&start=20#p109709
- https://forum.freecadweb.org/viewtopic.php?f=22&t=21330
In addition to the examples presented here have a look at FreeCAD source code src/Mod/TemplatePyMod/FeaturePython.py for more examples.