为在屏幕上合适的位置、以合适的视角显示三维装配诱导信息,提高诱导信息的信息量和立体感,提出一种基于零部件CAD特征包围盒模型的装配诱导信息自适应显示方法,包括屏幕显示区域自适应选择算法和最优视点选择算法.在屏幕显示区域自适应选择算法中,首先将屏幕区域划分成栅格,然后计算CAD特征包围盒顶点的屏幕坐标,并判断各屏幕栅格是否被包围盒占用,最终将屏幕上未被包围盒占用的最大连通区域作为屏幕非焦点区域,用于显示诱导信息.在最优视点选择算法中,利用CAD特征包围盒模型提出了一种综合考虑视图投影面积和立体特性的视点信息度量算子.实验结果表明,文中方法能够实现三维装配诱导场景屏幕显示区域及视点的在线选择,具有一定的智能性和通用性.
In order to display 3D assembly guiding information on suitable screen area in a proper viewpoint,this paper proposes an adaptive information display method for assembly guiding.The method includes adaptive selection of display area and viewpoint.For adaptive selection of display area,firstly the display screen is divided into many grids.Then this paper calculates the screen coordinates for vertexes of bounding boxes of CAD features and judges whether the screen grids are occupied by the bounding boxes of CAD features.Lastly the maximum connected region is chosen to display 3D guiding information.For automatic viewpoint selection,a viewpoint perception metric operator,which takes both projection area and stereoscopic characters into account,is put forward.Both methods proposed in this paper use bounding boxes of CAD features as input data,so they are intelligent and universal.