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 4