Abstract: In an apparatus and method for producing from an object having a three-dimensional shape a shape equivalent or analoguous to the three-dimensional shape, light is irradiated to the object in an optical cutting plane. The light is picked up by an image pick-up device, and two-dimensional positions of the light are obtained for each minute distance in a direction perpendicular to the optical cutting plane to determine its three dimensional shape.

Abstract: A vertical type roller mill for grinding a material including a grinding table and grinding rollers of a tire shape in contact with each other. The grinding table has a grinding surface composed of a surface portion constituting a portion of an imaginary conical surface having a apex located on a center axis of the table, and a curving surface portion located outwardly of and contiguous with the surface portion constituting the imaginary conical surface. The grinding rollers each have a grinding surface composed of a surface portion constituting a portion of another imaginary conical surface sharing the apex with the first mentioned conical surface, and a curving surface portion located outwardly of and contiguous with the surface portion constituting a portion of the last mentioned imaginary conical surface and having a greater curvature than the curving surface portion of the grinding surface of the grinding table.