[Solved] check if 2 faces overlap using Face.section method

[rluq]

I am trying to check if 2 parts overlap using the Face.section method. The attached images show the examples I refer to below.

In this example I have 3 cases, the first, where part1 and part2 overlap, the second, where part3 and part4 are in contact on 2 edges, and the third, where the parts do not overlap.

The following commands show how I have got the intersection (overlap1, overlap2, overlap3) between 2 parts using Face.section method:

Code: Select all

overlap1 = App.ActiveDocument.getObjectsByLabel('part1')[0].Shape.Faces[0].section(App.ActiveDocument.getObjectsByLabel('part2')[0].Shape.Faces[0])
Part.show(overlap1, "overlap1")

[case1.png]

Code: Select all

overlap2 = App.ActiveDocument.getObjectsByLabel('part3')[0].Shape.Faces[0].section(App.ActiveDocument.getObjectsByLabel('part4')[0].Shape.Faces[0])
Part.show(overlap2, "overlap2")

[case2.png]

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overlap3 = App.ActiveDocument.getObjectsByLabel('part5')[0].Shape.Faces[0].section(App.ActiveDocument.getObjectsByLabel('part6')[0].Shape.Faces[0])

[case3.png]

Considering that the 2 parts overlap only in the first case, I would like to find a rule that allows me to check if 2 parts overlap. I have tried to use the isValid method and the BoundBox property, but I don't know how to differentiate the different cases, especially the second one.

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>>> overlap1.isValid()
True
>>> overlap1.BoundBox
BoundBox (-692.421, 697.849, 0, -623.344, 750.705, 0)

>>> overlap2.isValid()
True
>>> overlap2.BoundBox
BoundBox (89.8585, 374.475, 0, 158.935, 703.134, 0)

>>> overlap3.isValid()
True
>>> overlap3.BoundBox
BoundBox (1.79769e+308, 1.79769e+308, 1.79769e+308, -1.79769e+308, -1.79769e+308, -1.79769e+308)

[edwilliams16]

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def testoverlap(overlap):
    if len(overlap.Edges) == 0:
        print("No overlap")
    else:
        w = Part.Wire(overlap.Edges)
        if w.isClosed():
            print("Shapes overlap")
        else:
            print("Shapes touch")

testoverlap(overlap1)
testoverlap(overlap2)
testoverlap(overlap3)

Works, but should fail in the pathological case where one shape completely surrounded and touched the other around its entire perimeter.

[edwilliams16]

Code: Select all

def testoverlap(overlap):
    if len(overlap.Edges) == 0:
        print("No overlap")
    else:
        se = Part.sortEdges(overlap.Edges)
        wires = [Part.Wire(s) for s in se]
        if any([w.isClosed() for w in wires]):
            print("Shapes overlap")
        else:
            print("Shapes touch")

I didn't think about the case where the overlap created multiple closed curves. This should fix that.

[rluq]

Thank you edwilliams16 for your answer!