So an easy thing to do in planar geometry is I want to make a line segment.
在平面几何里比较容易的一件事，就是做一个线段。
2
All planar structures are represented by a strike line and dip Angle.
一切面状构造均可用向线和倾斜角来表示。
3
Based on building the mathematical model of scanning process of Length alterable Line scanning Laser rapid prototyping system, a zoning algorithm for planar polygon is put forward.