Polygon covers 3d models

I use 2 type of entities:
- Cesium3dTileset
- Entity with Polygon graphics

Code for polygons:
options.polygon = new Cesium.PolygonGraphics({
   show: new Cesium.ConstantProperty(entity.visible),
   hierarchy : hierarchy,
   material : fillColor,
   extrudedHeight: <any>extrusion,
   outline: polygonHasBorder,
   outlineColor: lineColor,
   outlineWidth: lineWidth,
   heightReference: Cesium.HeightReference.CLAMP_TO_GROUND
viewer.entities.add(new Cesium.Entity(options));

Code for 3d tileset:
new Cesium.Cesium3DTileset({
   url: Cesium.IonResource.fromAssetId(options.IonResource.AssetID)

I expect to see polygons under the buildings from tileset, but the result is opposite. Look at the attached picture. Even if polygon is clamped to the ground, it's still is rendered above the buildings.

How can it be fixed? Probably the is a special settings to "stick" polygons to a terrain.

All you have to do is set the entity’s classificationType to:



Here’s a Sandcastle example:


Let me know if that works for you! What kind of application are you working on?