Design And Implementation Of Lightweight CAD Application System For Geometric Measurement

In recent years,intelligent manufacturing as a national strategy has become an important support for promoting the high-quality development of China’s manufacturing industry.Industrial measurement as an important component of intelligent manufacturing has also received widespread attention,but the domestic industrial measurement software started late,mostly to introduce foreign software,while the data generated in the measurement process is complex and fragmented,if the corresponding management and analysis method are not provided,it is difficult to deepen the measurement work in practical applications.Computer Aided Design(CAD)and geometric measurement are important parts of industrial measurement software,and secondary development based on existing CAD software will make the software itself bloated and have more redundancy.Therefore,the paper combines industrial measurement methods with CAD technology to design and develop a light-weight CAD application system for geometric measurements.The system uses Qt to realize the user interface design,based on Open SceneGraph(OSG)to complete scene management and data visualization,based on Open CASCADE(OCC)to complete the underlying model representation of elements,and realizes the conversion of OCC model to OSG nodes to display the model by studying the data organization of OCC and OSG.The system supports importing models,filtering data,annotation,picking up the element,roaming in the scene and manipulating elements,etc.The system can identify and measure the geometric elements in the image captured by the image measuring instrument,store elements based on OCC,provide a scene report area to assist users in browsing and analyzing the metric data generated during the measurement process,mark size information,support saving the contents of the scene in various file formats to the local machine,and provide a scene operation area to realize the operation of the metric data in the scene and a number of custom settings in the scene,and supports roaming through the scene data from multiple angles.In order to import DXF files into the scene,the system implements parsing algorithm of the DXF file after studying the internal data organization form.The system combines octree and Levels Of Detail(LOD)technology to manage scene data,and realizes roaming browsing through custom rovers.The system is organized by following the software engineering design principles.After comprehensive testing,the system meets the expected effect,and is practically applied in industrial measurement.