private bool SetEndTreatmentType(Document doc, RebarShape rebarShape)
{
    bool set = false;
    // check if end treatments are defined by rebar shape
    ReinforcementSettings settings = ReinforcementSettings.GetReinforcementSettings(doc);
    if (!settings.RebarShapeDefinesEndTreatments)
    {
        try
        {
            // can only be changed if document contains no rebars, area reinforcement or path reinforcement
            settings.RebarShapeDefinesEndTreatments = true;
        }
        catch (Exception e)
        {
            // cannot change the settings value
            TaskDialog.Show("Revit", e.Message);
        }
    }
    if (settings.RebarShapeDefinesEndTreatments)
    {
        EndTreatmentType treatmentType = EndTreatmentType.Create(doc, "Flame Cut");
        rebarShape.SetEndTreatmentTypeId(treatmentType.Id, 0);

        ElementId treatmentTypeId = EndTreatmentType.CreateDefaultEndTreatmentType(doc);
        rebarShape.SetEndTreatmentTypeId(treatmentTypeId, 1);

        set = true;
    }

    return set;
}

Private Function SetEndTreatmentType(doc As Document, rebarShape As RebarShape) As Boolean
    Dim [set] As Boolean = False
    ' check if end treatments are defined by rebar shape
    Dim settings As ReinforcementSettings = ReinforcementSettings.GetReinforcementSettings(doc)
    If Not settings.RebarShapeDefinesEndTreatments Then
        Try
            ' can only be changed if document contains no rebars, area reinforcement or path reinforcement
            settings.RebarShapeDefinesEndTreatments = True
        Catch e As Exception
            ' cannot change the settings value
            TaskDialog.Show("Revit", e.Message)
        End Try
    End If
    If settings.RebarShapeDefinesEndTreatments Then
        Dim treatmentType As EndTreatmentType = EndTreatmentType.Create(doc, "Flame Cut")
        rebarShape.SetEndTreatmentTypeId(treatmentType.Id, 0)

        Dim treatmentTypeId As ElementId = EndTreatmentType.CreateDefaultEndTreatmentType(doc)
        rebarShape.SetEndTreatmentTypeId(treatmentTypeId, 1)

        [set] = True
    End If

    Return [set]
End Function