This SAE Standard specifies a stationary test method for determining the masking effect caused by parts of the base machine with equipment as specified by the manufacturer on a visibility test circle around the machine from the eye position point of a seated operator. It specifies a method for evaluating the maskings that may be present. It applies to earthmoving machines which have a specific operatorâs station. It does not consider evaluation of maskings which may be present with operational movement of working tools.