// 鼠标绘制的两个点 const start = linePoint[0] const end = linePoint[1]
const direction = Cesium.Cartesian3.subtract( end, start, new Cesium.Cartesian3() )
const up = Cesium.Cartesian3.UNIT_Z const normal = Cesium.Cartesian3.cross(direction, up, new Cesium.Cartesian3()) Cesium.Cartesian3.normalize(normal, normal)