How to set arcType of Polyline in PolylineCollection


I have polylines being added to a polylineCollection:

const polylines = new PolylineCollection();
  for (let i = 0; i < vertices.length ; i++) {
        new Polyline(
            width: 10,
            positions: [
              state[viewerId].vertices[i - 1],
            material: new Material({
              fabric: {
                type: "Color",
                uniforms: {
                  color: new Color(1, 0.0, 0.0, 0.5),

I am using this to generate segments underneath a more complext polyline I have. However, when I am generating this polyline collection, it is using the arcType of NONE rather than GEODESIC

can someone please tell me how to make this polyline use the GEODESIC arcType? I have tried adding it as a property on the same level as the material like so: arcType: ArcType.GEODESIC, but it doesn’t seem to do any good.

Here is a screenshot of the issue I am seeing just in case my description was not clear:

The polyline that is working properly was added with the following syntax:

    polyline: {
      positions: positions,
      material: new ColorMaterialProperty(Color.WHITE.withAlpha(0.5)),

However, when I try adding the red line to the entities collection like this (as opposed to the primitives collection), I am unable to drill pick the red line and could not figure out why. Thank you for your help.

Hi @shane_benlolo,

its easier for us if you provide a sandcastle with code instead of screenshots, but after a quick look over your code it looks like you just forgot to add “Cesium” infront of the parameter:

arcType: Cesium.ArcType.GEODESIC

Or do you “import” Cesium and don’t have to add Cesium to all things?

Best, Lennart

Hey @lennart.imberg thanks for the response. Here is a sandcastle reproduction like you requested, Cesium Sandcastle

I am importing ArcType directly in my code, no leading Cesium required. When trying to add the arcType property to my Polyline, I am seeing the following TypeScript error:

'arcType' does not exist in type 
 show?: boolean; 
 width?: number; 
 loop?: boolean;
 material?: Material;  
 positions?: Cartesian3[]; 
 id?: any; 
 distanceDisplayCondition?: DistanceDisplayCondition;


I’m not familiar with TypeScript, but looking into the docs of Cesium, it seems the property arcType is only existant for entities (PolylineGraphics) and not for primitives (Polyline / PolylineCollection). That’s all I can tell, maybe some other folks can help here.

Best, Lennart