Research On Method For Direct Manipulation In Semantic Feature Modeling

In current commercial feature modeling systems, support for direct manipulation of features is not commonly available. As a result, re-designing is time-consuming due to the inefficient feedback, the insight given is rather poor, and user interaction often lacks intuitiveness. This is partly due to the lack of speed of current constraint solvers, but also to deficient interactive facilities.Firstly, a method is put forward by analyzing the process of direct manipulation in the semantic feature modeling system. In this way, the feature parameter value can be changed interactively, and the feedback of the model changes is real-time, allowing users to directly select feature parameter on the feature model. When the user is satisfied with the changes, the changed parameters can be accepted, and then the validity of the whole model can be checked. The key of this method is to provide real-time feedback when the model changes. In order to support changes of the interactive feature parameter values, many times of visual feedback per second must be generated and all the constraints must be solved at the same speed. According to the characteristics of direct manipulation model, the localization of the manipulation on the Cell-based semantics models is proposed, and the related algorithm and data structures are given.Secondly, this dissertation proposes a new solver for constraints on interactions, which is used to solve spatial overlap between feature shapes. This solver is based on sampling of the parameter space of the feature model. A Monte Carlo technique is applied to reduce the expected number of samples that are needed to find a valid model. The method in this paper is more available and effective than the traditional method which transforms a new constraint into another one. Finally, a powerful variety of 3D handles for real-valued feature parameters are provided, with a preview overlay facility for all modeling operations, and also how to use these handles in the process of direct manipulation is introduced.