REPRESENTATION OF 3-DIMENSIONAL SURFACE-TOPOGRAPHY IN CAD-SYSTEMS AND IMAGE-PROCESSING SOFTWARE

Adequate graphical representation of a measured machined surface for evaluation of its functional properties, is a well-known industrial problem. The use of profile curves has been the dominating technique in displaying the roughness and topography of a machined surface. The representation of topography is often made by assembling multiple-sampled 2-D profile curves (raster scan) to create the visual effect of a surface from a pre-selected viewing angle. During recent years, a number of 3-D surface measurement systems have been presented and commercial systems are now available on the market. This paper describes the possibilities with a system recently developed for representation of measured 3-D surface topography as wire frame or true surfaces. The system consists of a PC-computer for surface topography measuring and collecting of surface point coordinates connected to widespread CAD-systems and image processing software, CATIA, AutoCAD and Image, which are running on different computer platforms such as IBM-mainframe, Unix and VMS workstations as well as Apple Macintosh and IBM personal computers. Some of the advantages and limitations of the system and areas of application are demonstrated in a representation of bearing area and oil retaining volume of a cylinder liner.