Cesium Performance Issues

CesiumJS
1

Hi all,

I am trying to render a decently amount of polygons (~4000) on the cesium viewer on a computer with the following specs:

CPU: Intel Xeon E5-1620 @ 3.5GHz
GPU: Nvidia GTX 950
RAM: 16GB
(Cesium is running on Chrome)

However, for some reason, I am running into performance issues when I zoom into the polygons, and ONLY when I zoom into the polygons.

If cesium is full screen, and all of the rendered polygons take up the whole screen (at a zoom level where Canada covers my whole screen), there are no performance issues. The GPU usage is about 35% and CPU is about 20%.

Now, when I zoom into the polygons (at a zoom level where about half of Vancouver Island takes up the whole screen) there is an incredible amount of lag. The GPU usage skyrockets to 98-100%, but the CPU usage stays at about 15-20%.

I have tried fiddling around with various rendering settings:

viewer.scene.fxaa = false;
viewer.scene.fxaaOrderIndependentTranslucency = false;
viewer.scene.globe.maximumScreenSpaceError = 5;
contextOptions : {
   allowTextureFilterAnisotropic : false
}

etc...

However the only setting that helps is setting the viewer.resolutionScale to 0.25, and then the zoomed-in polygons don't lag nearly as much. However, at 25% of the normal resolution, it doesn't look too great.

Based on my tests, I am led to believe that this is some sort of software bug. It doesn't make any sense to me why rendering a few zoomed in polygons would be devastatingly taxing on the GPU, as rendering a whole lot more of polygons on the screen zoomed out is not.

Does anyone have some insight as to why this is? Any help would be greatly appreciated.

Cheers,
Dima

2

Also, I thought I'd mention that I am using a display that has a 1920x1080 resolution.

3

Dima,

Can you share the code you are using to create them? Are these polygons on terrain?

4

I create a new GeoJsonDataSource from a GeoJson string:

polygonType.dataSource =
        new Cesium.GeoJsonDataSource({name: polygonType.name});
    polygonType.dataSource.load(
        JSON.parse(geodata))
        .then(
        function()
        {
            polygonType.update = true;
        }
    );

Then I assign materials to each entity in:

polygonType.dataSource.entitites.values

Then I add the dataSource to the viewer:

viewer.dataSources.add(polygonType.dataSource)

5

I create a new GeoJsonDataSource from a GeoJson string:
polygonType.dataSource =
        new Cesium.GeoJsonDataSource({name: polygonType.name});
    polygonType.dataSource.load(
        JSON.parse(geodata))
        .then(
        function()
        {
            polygonType.update = true;
        }
    );

Then I assign materials to each entity in:

polygonType.dataSource.entitites.values

Then I add the dataSource to the viewer:

viewer.dataSources.add(polygonType.dataSource)

6

Also, my polygons are not on terrain.