Solid fats are most accurately measured by weight. However, bulk fats, notably shortening, may be measured by displacement.
To measure 2 cups/500 g fat, first put 2 cups/500 ml cold water in a transparent measuring cup. Add fat until the water level rises to 1 qt/1 L, then discard the water.
ALTERNATIVELY, to avoid wetting the fat, pack it in a dry measuring cup.