Principles of Orthographic Projection 正投影法原理 Form of Projection 投影的形成 Types of Projection 投影法分类 Features of Orthographic Projection正投影特性 Three-view of Component 物体的三视图 Exercises 练习题 请点击相应标题显示其内容 总绿
Principles of Orthographic Projection 正 投 影 法 原 理
Form of Projection投影的形成 Projection method When the line of projection passes through the object and the pre-established plane,there will be graphics produced on the plane.This method is called projection. 投影法： 投影法是投射线通过物体，向选定的平面投射， 并在该面上得到图形的方法。 Lines of projection Center of projection Projection Object Plane of projection 请点击鼠标左键显示后面内容
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Types of Projection投影法分类 Central projection method中投影法 (The central projection is mainly used for the pictorial drawings of buildings.一般多用于建筑图样) Projection method 投影法 VP. Parallel projection method平行投影法 It is used in most engineering drawings 广泛用于机械、电子、化工等行业的图样) 请点击鼠标左键显示后面内容
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Features of Orthographic Projection正投影特性 1.Authenticity: When planar features or lines are in parallel with the 真实性 projection plane,the projection shows the real shape or true length of the features being projected. 当平面图形或直线平行于投影面时，其投影反映实形或实长， 2.Accumulation: When planar features or lines are orthogonal to the 积聚性 projection plane,the projection accumulates to a line or a point. 当图形或直线垂直于投影面时，其投影积聚成一直线或点。 3.Homophyly: When planar features or lines are inclined to the 类似性 projection plane in general,the projection produces similar shapes of the original feature.The length of projected lines will be shorter than the real length. 当图形或直线倾斜于投影面时，图形的投影成类似形，线 段的投影长度比实长短。 请点击鼠标左键显正后面内空
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Three-View of Component物体的三视图 1.Form of three-view drawings 三视图的形成 A plan of an object is not always sufficient to describe it completely. 仅有物体的一个投影不能确定 它的空间形状。 How shall we do it？ 如何解决？ Single orthographic projection 单面正投影 Additional orthographic views can be drawn to sufficiently describe an object.It is necessary to use multiple views in engineering drawings 为了确定物体的空间形状，需要增加投影面。故在工程图 样中多采用多面视图。 靖点击鼠标左健显示后面内容
5 Single orthographic projection A plan of an object is not always sufficient to describe it completely. 仅有物体的一个投影不能确定 它的空间形状。 Additional orthographic views can be drawn to sufficiently describe an object. It is necessary to use multiple views in engineering drawings