PROBLEMS OF CREATING AND CHECKING SKELETON SURFACES IN CAD AND TOOLS FOR SOLVING THEM

The process of obtaining a computer model of a part whose shape contains complex (technical or architectural) surfaces is analyzed. The advantages of the constructive method of designing and creating computer models of such surfaces are shown. It is proposed to automate the creation of computer models of complex surfaces by forming their dot (point) or linear skeleton (frame) with subsequent approximation by spline surfaces passing through the skeletal elements. Cases of approximation are analyzed: it is required to create a patch of a single surface, it is required to create patches of several surfaces connected in one direction, it is required to create a two-dimensional set of connected patches of different surfaces. Symbols are introduced for standard commands for creating models of skeleton surfaces in the Kompas-3D CAD system, subtasks for creating computer models of skeleton surfaces are listed, and a general algorithm for solving them is shown. Subtasks of checking the accuracy of approximation of regular surfaces and their elements (generatrices) by splines are listed, and their solution using previously created tools is shown. The application of the created macro command for obtaining computer models of complex surfaces in the Kompas-3D CAD system is shown, and the results of accuracy assessment are given. The main advantage of the created tools is noted – they make the process of creating computer models of complex surfaces more flexible and at each step it becomes possible to assess the accuracy of the models.