You can't apply a hatch pattern to the face of a 3D object, but you could draw a boundary polyline around the face of the object and then hatch that. You will need to adjust your UCS and align your XY plane to each face you want to place the hatch pattern. You need to keep in mind that the hatch will not show up when you render though. The correct procedure is to apply materials to your 3D objects.
Wait a minute, how are you working with 3D objects? You're using LT!