断裂线用于定义和控制平滑度和连续性方面的表面特性。顾名思义，断裂线为线状要素。加入到地表模型中的断裂线对表面特性的描述具有重要作用。断裂线可以描述和强制执行对表面特性的更改。断裂线上的 z 值可以是常量，也可以是变量。
参考1：https://jingyan.baidu.com/article/d71306352a224613fdf475bc.html
参考2：https://www.lidar360.com/wp-content/LiDAR360-zh/ToolReference/ProfileEditing/BreaklineTool.html
How to add a breakline into a TIN dataset?
参考3：https://desktop.arcgis.com/en/arcmap/latest/manage-data/tin/add-tin-line-interactive-tool.htm
Line type—The type of breakline to be created. Choose either hard or soft as the line type. Hard and soft qualifiers for line and polygon feature types are used to indicate whether a distinct break in slope occurs on the surface at their location. A hard line is a distinct break in slope, while a soft line will be represented on the surface as a more gradual change in slope.
