Bottom: Plan view and cross section of a bionic shark skin (riblet film made by 3m) for reducing resistance on aircraft.
底部：计划和跨期的仿生鲨鱼皮节(里布·莱特电影3m公司制造)为减少飞机的阻力。
The shape of cross-section is an ellipse folded in half through one symmetry axis, and the axis keeps perpendicular with pinacoid-view.
断面形状为沿对称轴对折的椭圆，此对称轴始终垂直于轴截面，其方向与平面图上的流道中线无关。
The cross-section symbol of the pattern fill is a necessary material marker for the cross-sectional view of the solid object.
填充图剖面符号是机械制图、建筑制图中实体剖视图必不可少的材料标识。
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