Cesium polygon entities display with missing vertex

[jionghui]

There are 4 vertices created for the polygon entities, however, there are only 3 vertices displayed as shown below.

Tested on 1.43.0 :

var viewer = new Cesium.Viewer('cesiumContainer');
var entities = viewer.entities;
var arrPosList = [116.71705, 2.44717966, 18.6,
                  116.71705, 2.44717966, 7.1,
                  116.71704, 2.44719318, 7.1,
                  116.71704, 2.44719315, 18.6];
entities.add({
	polygon : {
		hierarchy : Cesium.Cartesian3.fromDegreesArrayHeights(arrPosList),
		perPositionHeight : true,
		material : Cesium.Color.fromRandom({alpha : 1.0})
	}
});
viewer.flyTo(viewer.entities);

[ggetz]

Hi @jionghui, the polygon primitive is designed to conform to the curvature of the ellipsoid, so it doesn't work for arbitrary polygons in space. See more discussion in #5907

Closing as a duplicate of #3349

Since you are trying to create a vertical polygon, maybe a wall will work for you.