Is it possiable to make entity position as the vertex of circular cone(cylinder)

CesiumJS
1

Currently, the entity position is the center of circular cone(cylinder). In my project, I
need to make the entity position as the vertex of it. Is it possible ? If yes, could you give me some guide .

I guess I need to modify the code in CylinderGeometry.createGeometry.

Many Thanks!

2

Hello,

In order to achieve this, you will need to have one entity define and position the cone, and one entity to define the point with a position at (longitude, latitude, coneHeight).

Let me know if you need an example.

Best,

Hannah

3

Thanks for your help. But I think it is a bit difficult to compute the position of the cone.
An example will be great help:-)

4

No problem. Here is an example:

var viewer = new Cesium.Viewer(‘cesiumContainer’);

var lon = -105.0;
var lat = 40.0;
var coneHeight = 4000.0;

viewer.entities.add({
position : Cesium.Cartesian3.fromDegrees(lon, lat, coneHeight),
point : {
pixelSize : 10,
color : Cesium.Color.YELLOW
}
});

viewer.entities.add({
position: Cesium.Cartesian3.fromDegrees(lon, lat, coneHeight/2.0),
cylinder : {
length : coneHeight,
topRadius : 0.0,
bottomRadius : 2000.0,
material : Cesium.Color.RED
}
});

viewer.zoomTo(viewer.entities);

``

-Hannah

5

Cool! great example:-)
I tested it successfully!

6

sorry to bother you again.
do you know how to rotated the cone with heading/pitch/roll from its apex, instead of from its center?

I checked this link https://groups.google.com/forum/#!topic/cesium-dev/f9ZiSWPMgus

But it seems the code only work with

Cesium.Math.toRadians(0.0),
Cesium.Math.toRadians(0.0),
Cesium.Math.toRadians(90.0)

,if I change it to another heading,pitch,roll, it won’t work.

Thanks!

Tudou

7

Hello,

You can use the orientation property to rotate the cone. Here is an example:

var viewer = new Cesium.Viewer(‘cesiumContainer’);

var position = Cesium.Cartesian3.fromDegrees(-105.0, 40.0, 200000.0);
var heading = Cesium.Math.toRadians(135);
var pitch = 45;
var roll = 0;
var hpr = new Cesium.HeadingPitchRoll(heading, pitch, roll);
var orientation = Cesium.Transforms.headingPitchRollQuaternion(position, hpr);

var redCone = viewer.entities.add({
name : ‘Red cone’,
position: position,
orientation : orientation,
cylinder : {
length : 400000.0,
topRadius : 0.0,
bottomRadius : 200000.0,
material : Cesium.Color.RED
}
});

viewer.zoomTo(viewer.entities);

``

Best,

Hannah

8

hmm,

But the orientation property will rotate the cone from its center, not from its apex.
I think we still need some translation, but I don’t know how to do this.