RECOGNIZING ALGORITHM FOR DIGITIZED ROTATIONAL PARTS

摘要

It is a well known fact that Reverse Engineering techniques involve the following steps: scanning the object, pre-processing a cloud of points, processing the cloud of points, redesigning, and manufacturing the part. Difficulties arise when processing clouds of points resulted from digitization, obtaining geometrical parameters of the scanned object itself and getting the final associated CAD model. This paper presents an algorithm for the recognition of a rotational part form. The part has been previously scanned and will be redesigned for re-manufacturing. To determine the surfaces of a rotational part, it is necessary to scan the part in order to obtain the cloud of points which is afterwards cleared of noise points. Beginning with the cloud of points, an algorithm is built that automatically determines the part's axis. The axis is then used to generate the required sections. The same tool also facilitates the recognition of simple, basic shapes like cylinders, cones and spheres. The points cloud data are stored in a text file. The text file contains all the points' coordinates of the cloud. After running the software on the data file we obtain the geometrical data necessary for the parametric model. This data can then be exported to a 3D design environment to redesign the digitized part. This paper contains two case studies in which a part was scanned and then, following the steps outlined above, the geometrical data of the part are obtained. With the geometrical data, the part can be modelled like a parameterized object.