rotate polygon around point

CesiumJS
1

Hey

Hello everyone

I’m trying to rotate a polygon around a point. How am I supposed to do this?

I’d love to help

Thank you

2

Hello,

There isn’t anything built into Cesium to handle this directly, but you can calculate the positions of the rotated points using a quaternion.

Here is a code example:

var viewer = new Cesium.Viewer(‘cesiumContainer’);
var positions = Cesium.Cartesian3.fromDegreesArray([-115.0, 37.0,
-115.0, 32.0,
-107.0, 33.0,
-102.0, 31.0,
-102.0, 35.0]);
var pointPosition = Cesium.Cartesian3.fromDegrees(-108, 38);
var quaternion = Cesium.Quaternion.fromAxisAngle(pointPosition, Cesium.Math.toRadians(1));
var rotationMatrix = Cesium.Matrix3.fromQuaternion(quaternion);
function getPositions(){
for (var i = 0; i < positions.length; i++) {
positions[i] = Cesium.Matrix3.multiplyByVector(rotationMatrix, positions[i], positions[i]);
}
return positions;
}

viewer.entities.add({
polygon : {
hierarchy : new Cesium.CallbackProperty(getPositions, false),
material : Cesium.Color.RED
}
});

viewer.entities.add({
position : pointPosition,
point : {
pixelSize : 10,
color : Cesium.Color.YELLOW
}
});

``

Best,

Hannah

3

Thank you Hannah :slight_smile:

‏בתאריך יום שלישי, 1 במרץ 2016, Hannah Pinkos pinkos.hannah@gmail.com כתב: