CesiumJS Viewer & Scene Setup

Reference for bootstrapping CesiumJS applications: Viewer, CesiumWidget, Ion/GoogleMaps/ITwinPlatform configuration, widgets, factory helpers, geocoder services, viewer mixins, Credits, and related enums.

Quick Start

import { Ion, Viewer, Terrain } from "cesium";
import "cesium/Build/Cesium/Widgets/widgets.css";

// Always set your Ion token before any other Cesium calls
Ion.defaultAccessToken = "YOUR_CESIUM_ION_ACCESS_TOKEN";

const viewer = new Viewer("cesiumContainer", {
  terrain: Terrain.fromWorldTerrain(),
});

Required HTML: <div id="cesiumContainer" style="width:100%;height:100vh"></div>

Ion & Platform Configuration

Cesium Ion

import { Ion } from "cesium";

Ion.defaultAccessToken = "YOUR_TOKEN";  // required for ion assets
Ion.defaultServer = "https://your-ion-server.example.com/"; // optional: self-hosted

IonResource

import { IonResource, Cesium3DTileset } from "cesium";

const resource = await IonResource.fromAssetId(96188);
const tileset = await Cesium3DTileset.fromUrl(resource);
viewer.scene.primitives.add(tileset);

Google Maps Platform

import { GoogleMaps, createGooglePhotorealistic3DTileset, Viewer, IonGeocodeProviderType } from "cesium";

GoogleMaps.defaultApiKey = "YOUR_GOOGLE_MAPS_API_KEY"; // optional: without key, served via ion

const viewer = new Viewer("cesiumContainer", {
  geocoder: IonGeocodeProviderType.GOOGLE, // required with Google 3D Tiles
});

const tileset = await createGooglePhotorealistic3DTileset({
  onlyUsingWithGoogleGeocoder: true,
});
viewer.scene.primitives.add(tileset);

iTwin Platform (experimental)

import { ITwinPlatform, ITwinData } from "cesium";

ITwinPlatform.defaultAccessToken = "YOUR_ITWIN_TOKEN";
const tileset = await ITwinData.createTilesetForIModel(viewer, "imodel-id");

// 1.140+ (#13208): Reality Data of type GaussianSplat3DTiles is now supported
const splats = await ITwinData.createTilesetForRealityDataId(
  iTwinId,
  realityDataId,
  ITwinPlatform.RealityDataType.GaussianSplat3DTiles,
);
viewer.scene.primitives.add(splats);

Viewer Constructor Options

new Viewer(container, options?) -- container is a DOM element or its string ID.

Widget Toggles

Option	Default	Purpose
animation	true	Playback controls
baseLayerPicker	true	Imagery/terrain switcher
fullscreenButton	true	Fullscreen toggle
vrButton	false	WebVR toggle
geocoder	IonGeocodeProviderType.DEFAULT	Search bar (false to hide)
homeButton	true	Reset to home view
infoBox	true	Entity info popup
sceneModePicker	true	2D/3D/Columbus toggle
selectionIndicator	true	Selection reticle
timeline	true	Time scrubber
navigationHelpButton	true	Mouse/touch help
projectionPicker	false	Perspective/ortho toggle

Scene & Rendering

Option	Default	Purpose
sceneMode	SceneMode.SCENE3D	Initial scene mode
scene3DOnly	false	Lock to 3D, saves GPU memory
shadows	false	Shadow casting
terrainShadows	ShadowMode.RECEIVE_ONLY	Terrain shadow mode
requestRenderMode	false	Render only on changes
maximumRenderTimeChange	0.0	Max sim-time delta for render
msaaSamples	4	MSAA (1 to disable)
orderIndependentTranslucency	true	Translucent ordering
mapMode2D	MapMode2D.INFINITE_SCROLL	2D scroll behavior

Layers & Terrain

Option	Default	Purpose
baseLayer	ImageryLayer.fromWorldImagery()	Base imagery (false for none; needs baseLayerPicker: false)
terrain	none	Async terrain helper (cannot combine with terrainProvider)
terrainProvider	EllipsoidTerrainProvider	Sync terrain provider
globe	new Globe()	false for no globe (space scenes)
skyBox	auto (WGS84)	false disables sky/sun/moon
skyAtmosphere	auto (WGS84)	false disables limb glow

Minimal Viewer (No Widgets)

import { Viewer, Ion, Terrain } from "cesium";
Ion.defaultAccessToken = "YOUR_TOKEN";

const viewer = new Viewer("cesiumContainer", {
  animation: false, baseLayerPicker: false, fullscreenButton: false,
  geocoder: false, homeButton: false, infoBox: false,
  sceneModePicker: false, selectionIndicator: false,
  timeline: false, navigationHelpButton: false,
  terrain: Terrain.fromWorldTerrain(),
});

CesiumWidget (Lightweight Alternative)

No UI widgets, no Knockout dependency. Suitable for custom UIs or embedding.

import { CesiumWidget, Ion } from "cesium";
Ion.defaultAccessToken = "YOUR_TOKEN";

const widget = new CesiumWidget("cesiumContainer", { shouldAnimate: true });
// Exposes: widget.scene, widget.camera, widget.entities

SceneMode Enum

Value	Description
SceneMode.SCENE3D	Standard 3D globe (default)
SceneMode.SCENE2D	Top-down orthographic map
SceneMode.COLUMBUS_VIEW	2.5D flat map with height
SceneMode.MORPHING	Transitioning between modes

import { Viewer, SceneMode } from "cesium";

const viewer = new Viewer("cesiumContainer", { sceneMode: SceneMode.SCENE2D });
viewer.scene.morphTo3D(2.0);          // animated transition
viewer.scene.morphToColumbusView(2.0);

Scene Configuration

const scene = viewer.scene;
scene.globe.depthTestAgainstTerrain = true; // entities interact with terrain
scene.globe.enableLighting = true;          // sun-based lighting

// Key sub-objects
scene.camera;           // Camera
scene.primitives;       // PrimitiveCollection
scene.groundPrimitives; // PrimitiveCollection (ground-clamped)
scene.imageryLayers;    // ImageryLayerCollection
scene.postProcessStages;

scene.requestRender();  // trigger frame in requestRenderMode

Factory Helpers

createOsmBuildingsAsync

import { createOsmBuildingsAsync, Cesium3DTileStyle } from "cesium";

// Default styling (colors from OSM tags)
const tileset = await createOsmBuildingsAsync();
viewer.scene.primitives.add(tileset);

// Custom style
const styled = await createOsmBuildingsAsync({
  style: new Cesium3DTileStyle({
    color: { conditions: [
      ["${feature['building']} === 'hospital'", "color('#0000FF')"],
      [true, "color('#ffffff')"],
    ]},
  }),
});

createGooglePhotorealistic3DTileset

import { createGooglePhotorealistic3DTileset, IonGeocodeProviderType } from "cesium";

// Must use Google geocoder
const viewer = new Viewer("cesiumContainer", { geocoder: IonGeocodeProviderType.GOOGLE });
const tileset = await createGooglePhotorealistic3DTileset({ onlyUsingWithGoogleGeocoder: true });
viewer.scene.primitives.add(tileset);

Terrain.fromWorldTerrain / fromWorldBathymetry

Preferred for the terrain constructor option. Non-blocking with error events.

import { Viewer, Terrain } from "cesium";

// World terrain with normals and water
const viewer = new Viewer("cesiumContainer", {
  terrain: Terrain.fromWorldTerrain({ requestVertexNormals: true, requestWaterMask: true }),
});

// Bathymetry (ocean floor)
const viewer2 = new Viewer("cesiumContainer", {
  terrain: Terrain.fromWorldBathymetry({ requestVertexNormals: true }),
});

Terrain Event Handling

import { Terrain, CesiumTerrainProvider } from "cesium";

const terrain = new Terrain(CesiumTerrainProvider.fromUrl("https://my-terrain.example.com"));
viewer.scene.setTerrain(terrain);

terrain.readyEvent.addEventListener((provider) => {
  viewer.scene.globe.enableLighting = true;
});
terrain.errorEvent.addEventListener((error) => console.error("Terrain failed:", error));

createWorldTerrainAsync / createWorldImageryAsync

Lower-level: return raw providers. Use when you need the provider directly.

import { createWorldTerrainAsync, createWorldImageryAsync, IonWorldImageryStyle } from "cesium";

const terrainProvider = await createWorldTerrainAsync({ requestVertexNormals: true });
viewer.terrainProvider = terrainProvider;

const imageryProvider = await createWorldImageryAsync({ style: IonWorldImageryStyle.AERIAL_WITH_LABELS });

IonWorldImageryStyle: AERIAL (default) | AERIAL_WITH_LABELS | ROAD

Geocoder Configuration

The geocoder option accepts false, an IonGeocodeProviderType, or a GeocoderService[].

IonGeocodeProviderType: DEFAULT | GOOGLE (required with Google tiles) | BING

import { Viewer, CartographicGeocoderService, IonGeocoderService, OpenCageGeocoderService } from "cesium";

// Multiple services (searched in order)
const viewer = new Viewer("cesiumContainer", {
  geocoder: [
    new CartographicGeocoderService(), // accepts "lat, lon" input
    new IonGeocoderService({ scene: viewer.scene }),
  ],
});

Custom GeocoderService

const myGeocoder = {
  async geocode(input, type) {
    // type: GeocodeType.SEARCH or GeocodeType.AUTOCOMPLETE
    const resp = await fetch(`https://api.example.com/search?q=${input}`);
    const data = await resp.json();
    return data.map((item) => ({
      displayName: item.name,
      destination: Cartesian3.fromDegrees(item.lon, item.lat),
    }));
  },
};
const viewer = new Viewer("cesiumContainer", { geocoder: [myGeocoder] });

Viewer Mixins

import { Viewer, viewerDragDropMixin, viewerCesium3DTilesInspectorMixin,
  viewerCesiumInspectorMixin, viewerPerformanceWatchdogMixin, viewerVoxelInspectorMixin } from "cesium";

const viewer = new Viewer("cesiumContainer");

// Drag-and-drop CZML/GeoJSON/KML loading
viewer.extend(viewerDragDropMixin, { dropTarget: "cesiumContainer", clearOnDrop: true });
viewer.dropError.addEventListener((handler, name, error) => console.error(error));

viewer.extend(viewerCesium3DTilesInspectorMixin);    // 3D Tiles debug panel
viewer.extend(viewerCesiumInspectorMixin);            // general scene inspector
viewer.extend(viewerPerformanceWatchdogMixin);        // low-FPS warning
viewer.extend(viewerVoxelInspectorMixin);             // voxel debug panel

Key Viewer Properties & Methods

Property	Type
viewer.scene	Scene
viewer.camera	Camera
viewer.entities	EntityCollection
viewer.dataSources	DataSourceCollection
viewer.imageryLayers	ImageryLayerCollection
viewer.terrainProvider	TerrainProvider
viewer.clock / clockViewModel	Clock / ClockViewModel
viewer.canvas	HTMLCanvasElement
viewer.screenSpaceEventHandler	ScreenSpaceEventHandler
viewer.selectedEntity / trackedEntity	Entity
viewer.shadows	boolean
viewer.resolutionScale	number (default 1.0)

await viewer.flyTo(entity, { duration: 3.0, offset: headingPitchRange }); // animated
await viewer.zoomTo(tileset);   // instant
viewer.destroy();               // free all resources

Credit & FrameRateMonitor

import { Credit, FrameRateMonitor } from "cesium";

// Custom credit (showOnScreen = true)
viewer.creditDisplay.addStaticCredit(new Credit("Data by Example Corp", true));

// Monitor frame rate
const monitor = FrameRateMonitor.fromScene(viewer.scene);
monitor.lowFrameRate.addEventListener(() => console.warn("Low FPS"));
monitor.nominalFrameRate.addEventListener(() => console.log("FPS recovered"));

Common Patterns

Production Viewer with Terrain and OSM Buildings

import { Ion, Viewer, Terrain, createOsmBuildingsAsync, Cartesian3, Math as CesiumMath } from "cesium";

Ion.defaultAccessToken = "YOUR_TOKEN";
const viewer = new Viewer("cesiumContainer", {
  terrain: Terrain.fromWorldTerrain(), animation: false, timeline: false,
});

viewer.scene.primitives.add(await createOsmBuildingsAsync());
viewer.scene.camera.flyTo({
  destination: Cartesian3.fromDegrees(-74.019, 40.6912, 750),
  orientation: { heading: CesiumMath.toRadians(20), pitch: CesiumMath.toRadians(-20) },
});

Space Scene (No Globe)

const viewer = new Viewer("cesiumContainer", {
  globe: false, skyAtmosphere: false, baseLayerPicker: false,
});

Explicit Render Mode (Low Power)

const viewer = new Viewer("cesiumContainer", {
  requestRenderMode: true, maximumRenderTimeChange: Infinity,
});
// Call viewer.scene.requestRender() after programmatic changes

Custom Base Layer

import { Viewer, ImageryLayer, OpenStreetMapImageryProvider } from "cesium";

const viewer = new Viewer("cesiumContainer", {
  baseLayerPicker: false,
  baseLayer: new ImageryLayer(new OpenStreetMapImageryProvider({
    url: "https://tile.openstreetmap.org/",
  })),
});

Columbus View with Web Mercator

import { Viewer, SceneMode, WebMercatorProjection } from "cesium";

const viewer = new Viewer("cesiumContainer", {
  sceneMode: SceneMode.COLUMBUS_VIEW, mapProjection: new WebMercatorProjection(),
});

Performance Tips

1. Set requestRenderMode: true for mostly-static apps. Reduces CPU/GPU and battery drain. Call scene.requestRender() after changes.
2. Use scene3DOnly: true when 2D/Columbus View is not needed. Saves GPU memory per geometry instance.
3. Disable unused widgets (animation: false, timeline: false) to reduce DOM overhead.
4. Set msaaSamples: 1 on low-power devices. Default 4 balances quality.
5. Lower resolutionScale (e.g., 0.75) on HiDPI displays for better frame rates.
6. Prefer Terrain.fromWorldTerrain() over await createWorldTerrainAsync() -- non-blocking with error events.
7. Enable requestVertexNormals: true on terrain for proper lighting at negligible cost.
8. Call viewer.destroy() when removing from DOM to free WebGL contexts.
9. Limit imagery layers to 2-3. Each adds a texture lookup per fragment.

See Also

• cesiumjs-camera -- Camera positioning, flyTo, lookAt, navigation constraints
• cesiumjs-entities -- Entity API, data sources, GeoJSON/KML/CZML loading
• cesiumjs-imagery -- Imagery providers, layer management, split-screen
• cesiumjs-terrain-environment -- Terrain providers, Globe, atmosphere, sky, lighting