was HashCode removed from TopAbs_Face?

[philosophical1337]

I am working with step files and when imported using read_step_file_with_names_colors you can always tell they contain many duplicate faces (obvious z-fighting).

I'm not sure if its just not noticeable when importing without colors due to the surfaces all being grey but anyway, I was using the following function to compare all the faces and discard duplicates which was working wonderfully until I updated to 7.8.1.

now I get the error message that HashCode attribute doesn't exist.

identifier = face.HashCode(-1)
                   ^^^^^^^^^^^^^
AttributeError: 'TopoDS_Face' object has no attribute 'HashCode'

here is my function:

    def removeDuplicateFaces(self, shape):
        # Create a compound to hold the result
        compound = TopoDS_Compound()
        builder = BRep_Builder()
        builder.MakeCompound(compound)

        uniqueFaces = {}

        explorer = TopExp_Explorer(shape, TopAbs_FACE)
        while explorer.More():
            face = explorer.Current()

            identifier = face.HashCode(-1)

            if identifier not in uniqueFaces:
                # Add the face to the result compound
                builder.Add(compound, face)
                # Store the identifier
                uniqueFaces[identifier] = face

            explorer.Next()

        return compound

[tpaviot]

The HashCode method was actually removed from OpenCascade itself. You can use the builtin hash function: identifier=hash(face)

[tpaviot]

I should have generated a deprecation warning when using the HashCode method

[philosophical1337]

this is just a guess but although the faces are geometrically identical, i think the actual face objects have small differences, so just hashing the object with the built in hash doesn't work at all.

I think the HashCode method was hashing only the geometric properties of the face and thus worked to find the identical faces, ignoring the differences in the object

[philosophical1337]

okay, i didn't realize that my code was effectively always returning only the first face and then discarding the rest, the HashCode(-1) just resulted in a hash of 1 every time.

i just ended up discarding everything but the first face and it works out the same, oops!