几年前发现Cesium的一个小惊喜，突然想起来，记录一下
viewer.entities.add({
polyline: {
positions: clampedCartesians,
arcType: Cesium.ArcType.NONE,
width:2,
material:new Cesium.PolylineOutlineMaterialProperty({
color: Cesium.Color.YELLOW,
}),
depthFailMaterial:new Cesium.PolylineDashMaterialProperty({
color: Cesium.Color.BLUE
})
},
});
