Want to use Polygon as ClassificationPrimitive

CesiumJS
1

In Sandcastle examples, Classification 3D tile, we can use boxgeometry as highlighting boundry. I want to use Polygon as highlighting boundry. I tried following example, it didn't throw any error, but didn't work either.

var extrudedPolygon = new Cesium.PolygonGeometry({
      polygonHierarchy : new Cesium.PolygonHierarchy(
      Cesium.Cartesian3.fromDegreesArray([
          -72.0, 40.0,
                                  -70.0, 35.0,
                                  -75.0, 30.0,
                                  -70.0, 30.0,
                                  -68.0, 40.0
        ])
      ),
      extrudedHeight: 200
    });

    //var geometry = Cesium.PolygonGeometry.createGeometry(polygon);
    var geometry1 = Cesium.PolygonGeometry.createGeometry(extrudedPolygon);
    /*Cesium.BoxGeometry.fromDimensions({
      vertexFormat : Cesium.PerInstanceColorAppearance.VERTEX_FORMAT,
      dimensions : new Cesium.Cartesian3(building.structures[index].dx, building.structures[index].dy, building.structures[index].dz)
    })*/
    var buildingHighlight = viewer.scene.primitives.add(new Cesium.ClassificationPrimitive({
      geometryInstances : new Cesium.GeometryInstance({
        geometry : geometry1,
        modelMatrix : modelMatrix,
        attributes : {
          color : Cesium.ColorGeometryInstanceAttribute.fromColor(new Cesium.Color(1.0, 0.0, 0.0, 0.5)),
          show : new Cesium.ShowGeometryInstanceAttribute(true)
        },
        id : 'volume'
      }),
      classificationType : Cesium.ClassificationType.BOTH
    }));

2

Hi there,

The documentation for ClassificationPrimitive lists the supported geometry types:

Valid geometries are BoxGeometry, CylinderGeometry, EllipsoidGeometry, PolylineVolumeGeometry, and SphereGeometry.

So you’ll need to use one of those geometries.

Thanks!

Gabby

3

I tried to implement PolylineVolumeGeometry, but couldn't succeed on using as ClassificationPrimitive. I was able to generate polygeometry with Round volume from samples for PolylineVolumeGeometry.

I'm able to generate polygon outline, but not able to generate its vertical volume. e.g.

var greenBox = viewer.entities.add({
    name : 'Green box with beveled corners and outline',
    polylineVolume : {
        positions : Cesium.Cartesian3.fromDegreesArray([
      -74.41453200422134, 40.93542704749751,
      -73.36827859024918, 40.9611033533233,
      -73.16152373946669, 41.38956253083078,
      -74.29436811233255, 41.54438381912347
        ]),
        //shape : computeStar(7, 70, 50),
    shape :[
      new Cesium.Cartesian2(Cesium.Math.toDegrees(-74.41453200422134), Cesium.Math.toDegrees(40.93542704749751)),
      new Cesium.Cartesian2(Cesium.Math.toDegrees(-73.36827859024918), Cesium.Math.toDegrees(40.9611033533233)),
      new Cesium.Cartesian2(Cesium.Math.toDegrees(-73.16152373946669), Cesium.Math.toDegrees(41.38956253083078)),
      new Cesium.Cartesian2(Cesium.Math.toDegrees(-74.29436811233255), Cesium.Math.toDegrees(41.54438381912347))],
        material : Cesium.Color.GREEN.withAlpha(0.5),
        outline : true,
        outlineColor : Cesium.Color.BLACK
    }
});

I'm sure I'm making some mistake in shape parameter.

4

Don’t use Cesium.Math.toDegrees. The Cartesian2 is an offset from the center potion from which to draw the shape.

shape : [new Cesium.Cartesian2(-50000, -50000),

new Cesium.Cartesian2(50000, -50000),

new Cesium.Cartesian2(50000, 50000),

new Cesium.Cartesian2(-50000, 50000)],

``

5

Hi Gabby Getz
Do you have any sample where any other geometry is being used in ClassificationPrimitive?

6

Example with boxes, ellipsoids, and spheres.

Example with polygons.

Additionally, you can search for “classification” in Sandcastle to get all the examples that use it.