Duplicated Shape artifacts when using Part::FeaturePython with App::GroupExtensionPython about freecad

[luzpaz]

@easyw would you be able to help with this issue ?

[morganrallen]

would certainly help where I can. So far I've attempted to find a cause, or workaround from the Python side of things without much success. I'm working on a minimal macro to recreate the issue, this should be helpful debugging the issue further.

[morganrallen]

ok, here's a minimal macro that I think demonstrates the problem. During the actual FeaturePython and ViewProvider creation parts, nothing is actually added to the PythonFeature.Shape. Despite this, when the Body is added as a group member, the PythonFeature assumes the shape of it's child, effectively duplicating it.

import FreeCAD as App
import Part

def create(obj_name):
    obj = App.ActiveDocument.addObject('Part::FeaturePython', obj_name)

    box(obj)

    ViewProviderBox(obj.ViewObject)

    return obj

class box():
    def __init__(self, obj):
        obj.addExtension('App::GroupExtensionPython')


class ViewProviderBox:

    def __init__(self, obj):
        obj.Proxy = self
        obj.addExtension('Gui::ViewProviderGroupExtensionPython')

    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 canDropObject(self, obj):
        return True

o1 = create('test')

body = App.ActiveDocument.addObject('PartDesign::Body','Body')
box = App.ActiveDocument.addObject('PartDesign::AdditiveBox','Box')

box.Length = 10
box.Width = 10
box.Height = 10

body.addObject(box)
o1.addObject(body)
o1.Placement.Base.x = 12

App.ActiveDocument.recompute()

[morganrallen]

Couple other things I've noticed, that seem like problematic behavior...

If the Placement on the Feature is changed, it's Shape is moved, but the Body in the Group does not. My feeling for how this should work, is if a Group is moved, all of it's Children should also be moved accordingly. Also in this case the Placement of neither the Feature nor its Shape are updated, which I >guess< hints at a rendering error?