Device and method for providing allowable assignment range of multiple parameters in computer aided design system

Abstract

A device for providing an allowable assignment range of multiple parameters in a computer aided design system and a method thereof. The device comprises: an acquisition unit, which acquires a two-dimensional model from a computer-aided design system; a first input unit which is determined by a user to divide the size parameters of the two-dimensional geometric constraint in the acquisition unit into a fixed size parameter set and a to-be-modified size parameter set; a first creating unit which is used for calculating an allowable assignment range of each size parameter to be modified and displaying the allowable assignment range to a user; a second input unit which is used for selecting, editing and updating any size parameter to be modified by a user; a second creating unit which is used for updating the coordinate variables of the geometric body according to the parameter values of the size parameters of all the current geometric constraints, wherein the first creating unit is used for constructing a corresponding equality constraint function for each size parameter to be modified and solving to obtain a final value domain interval, and the final value domain interval is respectively used as an allowable assignment range of the corresponding size parameter to be modified.

Description

technical field [0001] The present invention mainly relates to the field of computer-aided design, in particular to a device and a method for providing an allowable value assignment range of multiple parameters in a computer-aided design system. Background technique [0002] Computer-aided design is a digital method that first creates corresponding 2D drawings and 3D models for products through computer-aided design software before actually producing real products. With computer-aided design software, users can simulate and modify designs, opening the door to rapid introduction of innovative and differentiated products. The development of computer-aided design software has roughly gone through several stages, including wireframe modeling design, curve surface modeling design, solid modeling design, and parametric design. Among them, the wireframe modeling design can only express the basic geometric information of the parts, but cannot effectively express the topological rel...

AI Technical Summary

Problems solved by technology

In practical applications, the complexity of most products will far exceed the back cover of the desktop computer case, so it is more difficult to obtain the effective assignment range of multiple parameters

Therefore, the problem of the allowable assignment range of multiple parameters has not been effectively resolved

For a large number of geometric constraint systems that cannot be decomposed into triangular subproblems, this type of constructive method cannot be applied

[0016] 2. Secondly, when it is necessary to calculate the allowable assignment range of multiple parameters in a two-dimensional model, this type of method will ignore some constraints, resulting in the incomplete allowable assignment range of the calculated parameters, so it is not suitable for solving the allowable range of multi-parameters. Assignment scope

(2) This high-dimensional space is difficult to be directly understood and used by users

1) All existing commercial CAD systems can provide mature geometric constraint solving functions; however, none of the commercial CAD systems can provide the user with the allowable value range of the parameter when editing the parameter

[0024] 2) A considerable amount of research has been accumulated on geometric constraint solving problems. In the article "Review of Geometric Constraint Solving Research" published by Gao Xiaoshan and Jiang Kun in 2004, nearly a hundred papers on geometric constraint solving problems were cited. In addition, in 2011 Hoffmann's review article "Geometric constraint solving in parametriccomputer-aided design" cited hundreds of geometric constraint solving literatures, which can prove the maturity of geometric constraint solving technology; in contrast, the allowable value range of calculation size parameters Due to the complexity of the problem, breakthrough progress has not been made for a long time, and there are very few research results in this area. There are only a few literatures on the calculation of the allowable assignment range of parameters

[0025] 3) The problem of solving geometric constraints is essentially a problem of solving equations, and there have been a lot of work on solving equations throughout the ages; the problem of calculating the allowable value assignment range of parameters is essentially to study the complex nonlinear equations under what conditions have or have no solution, making the problem more challenging than the simple problem of solving equations

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