The Use Of Cnc Machine Tools To Achieve Coordinate Measuring - Reverse Modeling

How to deal with the datam from the machine center is discussed in the topic. The research on constraints based structural feature model reconstruction method is a new aspect in reversing engineering, which can be used to reconstruct more reliable model. Modeling in current 3D CAD softwares such as CATIA,Pro/Engineer are mainly based on sketch design. According to the idea of modeling and on the basis of segmenting 3D measured date with feature design intention, this thesis studies the reconstruction methods of model sketch-based feature such as extruded and rotational features in structural part models. The main contents of this thesis are as follows:(1)The technique of sketch Profile fitting is studied in this thesis. First the sketch/datam Plane is fitted by Least-Square distance,then the extruded direction or axis with the flank points of the cloud is extracted in quadratic paogramming arithmetic, and certain Points projected to gain 2D sketched datam. Feature Points are defined to segment the sketch datam,and the sketch Profile is generated by fitting separately the line and circle segment.(2) The 2D geometry constraints between or among the features are classified. the expression of ZD constrains and the resolvent about constrains are discussed the algorithms and process of resolving constrains are demonstrated.(3) The generation methods of sketch-based feature model reconstruction are presented in this thesis. Experimental results show that the methods presented here are reliable.(4) It analyses and introduces the geometry data point optimized measure plan and the precision question, in the curved surfaces measure, it provides the method of carries on the data point according to the characteristic point of the gathering.Preliminarily study the measuring methods and path plan of some simple even curve plane in three-dimensional space. Experimental results show that the methods presented here are reliable.