def get_boundary(mesh):  # From trails
    """ Create triangulation boundary """
    import Part
    import itertools as itools
    from collections import Counter
    from ast import literal_eval

    facet_pidx = mesh.Topology[1]
    edges = itools.chain(*(itools.permutations(pidx, 2) for pidx in facet_pidx))
    count = Counter((str(edge) for edge in edges))
    double_boundary = list((literal_eval(k) for k, v in count.items() if v == 1))

    boundary = double_boundary[:1]
    for candidate in double_boundary[1:]:
        if candidate in boundary or candidate[::-1] in boundary:
            pass
        else:
            boundary.append(candidate)

    def mkEdge(p1, p2):
        return Part.makeLine((p1.x, p1.y, p1.z), (p2.x, p2.y, p2.z))

    points = mesh.Points
    edges = []
    for p1, p2 in boundary:
        edges.append(mkEdge(points[p1], points[p2]))

    wires = []
    for opening in Part.sortEdges(edges):
        wires.append(Part.Wire(opening))
    return Part.makeCompound(wires)