提出了一种基于中间模型的可展回转型装配体展开和自动化出图方法,以保持可展回转型装配体二维图纸与三维模型的一致性。通过引入中间模型的概念,将三维空间的回转型装配体展平到平面状态,以方便投影出图。给出了管道系统展开的通用方法,设计了圆柱形和圆台形装配体到中间模型的坐标转换算法,采用管道离散化后进行坐标转换,再进行管道重构的方法实现了管道的展开;针对企业标准定制了出图模板,利用附着在中间模型上的几何位置和属性信息,实现了部分自动化的二维出图。通过将所开发的系统应用在某航天企业中,表明了所提方法的正确性和实用性。
A method to unfold the developable rotary assembly and to automatic drawing of engineering drafting based on intermediate model was proposed to maintain the consistency between 3D model and 2D drafting. The concept of intermediate model was introduced to unfold 3D developable rotary assembly into planar state for facility projecting. General unfolding method for pipeline systems was presented. Two coordinate transformation algorithms from 3D model space to 3D intermediate model for cylindrical and conical assembly were exploited. Discrete pipeline was used to conduct coordinate transformation,and pipeline reconstruction method was employed to unfold pipelines. A set of customized drafting templates based on enterprise standard was set up,and the 2D semi-automatic drawing of engineering drafting was achieved with geometric location and attributes in intermediate model. The developed system was applied in aerospace enterprise. The results revealed the effectiveness and practicability of the proposed method.