loading multiple entities through CZML causing very poor rendering performance

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Muhammad Usman

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Jul 1, 2016, 1:09:35 AM7/1/16

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Hi everyone,

I am working on an application to render multiple entities (i.e. average of 500). I am loading the entities from a CZML file. Each entity has an array of positions with thousands of position entries in it and I am interpolating the entity over these positions. This works fine for fewer entities i.e. 10 - 15 entities. My ultimate aim is to render ~500 entities but system is showing super poor performance with even 50 entities. Loading part is working good but the movement/interpolation of entities over their corresponding positions is deadly slow and lagging a lot. Any thoughts on how can I achieve high rendering performance?

Here is my CZML file:

[
 {
   "id":"document",
   "name":"test_document",
   "version":"1.0"
 },
 {
   "id":"1",
   "name":"Entity-1",
   "description":"some info",
   "point":{
     "color":{
       "rgbaf":[
         1,0,1,1
       ]
     },
     "outlineColor":{
       "rgbaf":[
         0,0,0,1
       ]
     },
     "outlineWidth":2,
     "pixelSize":4,
     "show":true
   },
   "path":{
     "width":1,
     "trailTime":7969,
     "leadTime":0,
     "show":false
   },
   "position":{
     "referenceFrame":"INERTIAL",
     "epoch":"2016-06-30T00:00:00Z",
     "cartesian":[
          thousands of positions....
     ]
   }
 },
{
// for entity 2
},
{
// for entity 50
}
]

This is how I am loading the CZML:

var promise = new Cesium.CzmlDataSource.load('data.czml');
var _dataSource;

promise.then(function(dataSource) {
	_dataSource = dataSource;

viewer.dataSources.add(dataSource);


        //Get the array of entities
        var entities = _dataSource.entities.values;
			
	for (let i = 0; i < entities.length; i++) {
		let entity = entities[i];
		
		entity.point.pixelSize = new Cesium.CallbackProperty(function(time,result){
			updatePointSize(entity.name, function(size){
				sizes[entity.name] = size;
			});
			return sizes[entity.name];				
		}, false);	
	}
});

Any thoughts on how to improve the rendering performance? I am wishing to see a smooth simulation (interpolation) of points. This behavior is working well with fewer entities (i.e. with 10 - 15 points) but not for ~50 entities (points). And my ultimate hope is to achieve this smooth fast rendering (interpolation/simulation) for around ~500 entities (points).

Muhammad Usman

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Jul 1, 2016, 4:30:27 PM7/1/16

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Never mind!

Figured it out. It's the "Path" in the data set with resolution=3 which was eating all the performance. Thanks to this: https://groups.google.com/d/msg/cesium-dev/hu_J2jqpLnI/bt7bIrAMBAAJ

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