def loadNeutral(filename, c="gold", alpha=1, wire=False, bc=None):
    """Reads a `Neutral` tetrahedral file format. Return an ``Actor(vtkActor)`` object."""
    if not os.path.exists(filename):
        colors.printc("~noentry Error in loadNeutral: Cannot find", filename, c=1)
        return None

    coords, connectivity = convertNeutral2Xml(filename)
    poly = buildPolyData(coords, connectivity, indexOffset=0)
    return Actor(poly, c, alpha, wire, bc)
Reads a `Neutral` tetrahedral file format. Return an ``Actor(vtkActor)`` object.