CesiumJS 3D Tiles

Version baseline: CesiumJS v1.139 (ES module imports, async factory methods).

Loading a Tileset

Always use async factory methods -- never call the constructor directly.

import { Cesium3DTileset, HeadingPitchRange, Math as CesiumMath } from "cesium";

// From a URL
const tileset = await Cesium3DTileset.fromUrl(
  "https://example.com/tileset.json",
  { maximumScreenSpaceError: 16 }, // lower = higher quality
);
viewer.scene.primitives.add(tileset);
viewer.zoomTo(tileset, new HeadingPitchRange(
  0.0, CesiumMath.toRadians(-25.0), tileset.boundingSphere.radius * 2.0,
));

// From Cesium ion
const tileset = await Cesium3DTileset.fromIonAssetId(75343);
viewer.scene.primitives.add(tileset);

// Google Photorealistic 3D Tiles
import { createGooglePhotorealistic3DTileset } from "cesium";
const google3D = await createGooglePhotorealistic3DTileset({
  onlyUsingWithGoogleGeocoder: true,
});
viewer.scene.primitives.add(google3D);

// OSM Buildings
import { createOsmBuildingsAsync } from "cesium";
const osmBuildings = await createOsmBuildingsAsync();
viewer.scene.primitives.add(osmBuildings);

Key Constructor Options

Option	Default	Purpose
maximumScreenSpaceError	16	LOD quality threshold (pixels)
cacheBytes	536870912	Tile cache trim target (bytes)
maximumCacheOverflowBytes	536870912	Extra cache headroom
shadows	ShadowMode.ENABLED	Shadow casting/receiving
modelMatrix	Matrix4.IDENTITY	Root transform
clippingPlanes	undefined	ClippingPlaneCollection
clippingPolygons	undefined	ClippingPolygonCollection (WebGL 2)
enableCollision	false	Camera collision with tileset surface
pointCloudShading	undefined	Point attenuation options object
classificationType	undefined	TERRAIN, CESIUM_3D_TILE, or BOTH
dynamicScreenSpaceError	true	Horizon LOD optimization
foveatedScreenSpaceError	true	Center-screen tile priority
preloadFlightDestinations	true	Prefetch tiles at flight target
featureIdLabel	"featureId_0"	EXT_mesh_features ID set label
backFaceCulling	true	Cull back faces per glTF material

Tileset Events

tileset.loadProgress.addEventListener((pending, processing) => {
  if (pending === 0 && processing === 0) console.log("Loaded");
});
tileset.initialTilesLoaded.addEventListener(() => { /* first view ready */ });
tileset.allTilesLoaded.addEventListener(() => { /* all visible tiles ready */ });
tileset.tileLoad.addEventListener((tile) => { /* tile content loaded */ });
tileset.tileUnload.addEventListener((tile) => { /* tile evicted from cache */ });
tileset.tileFailed.addEventListener(({ url, message }) => {
  console.error(`Tile ${url}: ${message}`);
});
// Per-frame manual styling
tileset.tileVisible.addEventListener((tile) => {
  const content = tile.content;
  for (let i = 0; i < content.featuresLength; i++) {
    content.getFeature(i).color = Cesium.Color.fromRandom();
  }
});

Runtime Properties

tileset.show = false;                     // toggle visibility
tileset.maximumScreenSpaceError = 8;      // increase quality
const { center, radius } = tileset.boundingSphere;

import { Matrix4, Cartesian3 } from "cesium";
tileset.modelMatrix = Matrix4.fromTranslation(new Cartesian3(0, 0, 100));

Declarative Styling

Assign a Cesium3DTileStyle to tileset.style. Expressions reference feature properties with ${PropertyName}.

import { Cesium3DTileStyle } from "cesium";

// Color by height conditions
tileset.style = new Cesium3DTileStyle({
  color: {
    conditions: [
      ["${Height} >= 100", "color('purple', 0.5)"],
      ["${Height} >= 50",  "color('red')"],
      ["true",             "color('blue')"],
    ],
  },
  show: "${Height} > 0",
});

// Use defines to simplify repeated sub-expressions
tileset.style = new Cesium3DTileStyle({
  defines: { material: "${feature['building:material']}" },
  color: {
    conditions: [
      ["${material} === null",    "color('white')"],
      ["${material} === 'glass'", "color('skyblue', 0.5)"],
      ["${material} === 'brick'", "color('indianred')"],
      ["true",                    "color('white')"],
    ],
  },
});

// Show/hide by property
tileset.style = new Cesium3DTileStyle({
  show: "${feature['building']} === 'office'",
});

// Point cloud styling
tileset.style = new Cesium3DTileStyle({
  color: "vec4(${Temperature})",
  pointSize: "${Temperature} * 2.0",
});

tileset.style = undefined; // reset to default appearance

Color Blend Modes

import { Cesium3DTileColorBlendMode } from "cesium";
tileset.colorBlendMode = Cesium3DTileColorBlendMode.REPLACE; // HIGHLIGHT | REPLACE | MIX
tileset.colorBlendAmount = 0.5; // only used with MIX

Feature Picking and Properties

Scene.pick returns Cesium3DTileFeature for 3D Tiles features. Modifications persist until the owning tile is evicted from the cache.

import {
  ScreenSpaceEventHandler, ScreenSpaceEventType,
  Cesium3DTileFeature, Color,
} from "cesium";

const handler = new ScreenSpaceEventHandler(viewer.scene.canvas);

// Hover: read properties
handler.setInputAction((movement) => {
  const feature = viewer.scene.pick(movement.endPosition);
  if (feature instanceof Cesium3DTileFeature) {
    const ids = feature.getPropertyIds();
    for (const id of ids) console.log(`${id}: ${feature.getProperty(id)}`);
    feature.color = Color.YELLOW; // highlight
  }
}, ScreenSpaceEventType.MOUSE_MOVE);

// Click: inspect a single property
handler.setInputAction((movement) => {
  const feature = viewer.scene.pick(movement.position);
  if (feature instanceof Cesium3DTileFeature) {
    console.log("Height:", feature.getProperty("Height"));
    feature.setProperty("selected", true); // write custom property
    feature.show = false;                  // hide individual feature
  }
}, ScreenSpaceEventType.LEFT_CLICK);

Inherited Metadata (3D Tiles 1.1 / EXT_structural_metadata)

// Searches: batch table -> content -> tile -> subtree -> group -> tileset
const value = feature.getPropertyInherited("semanticOrPropertyName");

Clipping Planes

ClippingPlaneCollection clips via half-space planes in the tileset's local coordinate system.

import {
  ClippingPlane, ClippingPlaneCollection,
  Cartesian3, Color, Matrix4,
} from "cesium";

const clippingPlanes = new ClippingPlaneCollection({
  planes: [new ClippingPlane(new Cartesian3(0.0, 0.0, -1.0), 0.0)],
  edgeWidth: 1.0,
  edgeColor: Color.WHITE,
  unionClippingRegions: false, // false = intersection (AND); true = union (OR)
});

const tileset = await Cesium3DTileset.fromUrl(url, { clippingPlanes });
// Or: tileset.clippingPlanes = clippingPlanes;

// Offset the clip boundary at runtime
clippingPlanes.modelMatrix = Matrix4.fromTranslation(new Cartesian3(0, 0, 50));
clippingPlanes.get(0).distance = 25.0;

Clipping Polygons

ClippingPolygonCollection clips using arbitrary polygons. WebGL 2 only.

import { ClippingPolygon, ClippingPolygonCollection, Cartesian3 } from "cesium";

const polygon = new ClippingPolygon({
  positions: Cartesian3.fromDegreesArray([
    -105.0077, 39.7519, -105.0095, 39.7504,
    -105.0071, 39.7513, -105.0077, 39.7519,
  ]),
});

tileset.clippingPolygons = new ClippingPolygonCollection({
  polygons: [polygon],
  inverse: false, // false = clip inside polygon; true = clip outside
});

// Also works on the globe
viewer.scene.globe.clippingPolygons = new ClippingPolygonCollection({
  polygons: [polygon],
});

Point Cloud Shading

const tileset = await Cesium3DTileset.fromUrl(pointCloudUrl, {
  pointCloudShading: {
    attenuation: true,           // scale points by geometric error
    geometricErrorScale: 1.0,
    maximumAttenuation: 10,      // max pixel size; undefined = maximumScreenSpaceError
    eyeDomeLighting: true,       // depth-aware edge enhancement
    eyeDomeLightingStrength: 1.0,
    eyeDomeLightingRadius: 1.0,
    backFaceCulling: false,      // requires normals in point data
    normalShading: true,
  },
});
viewer.scene.primitives.add(tileset);

// Runtime adjustment
tileset.pointCloudShading.eyeDomeLightingStrength = 2.0;

Voxel Primitives

VoxelPrimitive renders volumetric data from a Cesium3DTilesVoxelProvider. Shapes: BOX, CYLINDER, ELLIPSOID (see VoxelShapeType).

import { VoxelPrimitive, Cesium3DTilesVoxelProvider, CustomShader } from "cesium";

const provider = await Cesium3DTilesVoxelProvider.fromUrl("voxel/tileset.json");

const voxelPrimitive = new VoxelPrimitive({
  provider,
  customShader: new CustomShader({
    fragmentShaderText: `void fragmentMain(FragmentInput fsInput, inout czm_modelMaterial material) {
      material.diffuse = fsInput.metadata.a.rgb;
      material.alpha = fsInput.metadata.a.a;
    }`,
  }),
});
viewer.scene.primitives.add(voxelPrimitive);
voxelPrimitive.nearestSampling = true;
viewer.camera.flyToBoundingSphere(voxelPrimitive.boundingSphere, { duration: 0 });

// For voxel shader authoring — struct availability, raymarching semantics, metadata
// access — see the cesiumjs-custom-shader skill. This skill covers VoxelPrimitive setup.

// Optional inspector widget
viewer.extend(Cesium.viewerVoxelInspectorMixin);
viewer.voxelInspector.viewModel.voxelPrimitive = voxelPrimitive;

I3S Data Provider

Load Esri I3S scene layers (3D Objects, IntegratedMesh, Building Scene Layer).

import { I3SDataProvider, ArcGISTiledElevationTerrainProvider, Ellipsoid, Rectangle } from "cesium";

const geoidService = await ArcGISTiledElevationTerrainProvider.fromUrl(
  "https://tiles.arcgis.com/tiles/.../EGM2008/ImageServer",
);
const i3sProvider = await I3SDataProvider.fromUrl(
  "https://tiles.arcgis.com/tiles/.../SceneServer/layers/0",
  { geoidTiledTerrainProvider: geoidService },
);
viewer.scene.primitives.add(i3sProvider);

const center = Rectangle.center(i3sProvider.extent);
center.height = 5000.0;
viewer.camera.setView({
  destination: Ellipsoid.WGS84.cartographicToCartesian(center),
});

Gaussian Splats

Loaded as standard 3D Tiles; CesiumJS handles KHR_gaussian_splatting automatically.

const splats = await Cesium3DTileset.fromIonAssetId(3667783);
viewer.scene.primitives.add(splats);
viewer.zoomTo(splats);

Classification

Drape tileset geometry as a classification overlay on terrain or other tilesets.

import { Cesium3DTileset, ClassificationType } from "cesium";
const classified = await Cesium3DTileset.fromUrl(url, {
  classificationType: ClassificationType.BOTH, // TERRAIN | CESIUM_3D_TILE | BOTH
});
viewer.scene.primitives.add(classified);

Adjusting Tileset Height

import { Cartographic, Cartesian3, Matrix4 } from "cesium";
const cartographic = Cartographic.fromCartesian(tileset.boundingSphere.center);
const surface = Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 0.0);
const offset = Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, heightOffset);
const translation = Cartesian3.subtract(offset, surface, new Cartesian3());
tileset.modelMatrix = Matrix4.fromTranslation(translation);

Performance Tips

1. Keep maximumScreenSpaceError as high as acceptable (16 default; 32+ for mobile).
2. Leave dynamicScreenSpaceError: true for street-level views with large tilesets.
3. Leave foveatedScreenSpaceError: true to prioritize center-screen tiles.
4. Size cacheBytes and maximumCacheOverflowBytes to device memory (512 MB each default).
5. Use preloadFlightDestinations: true to prefetch tiles at the camera flight target.
6. Enable skipLevelOfDetail: true for large replacement-refined tilesets to reduce memory.
7. Avoid maximumScreenSpaceError below 4 -- diminishing returns, many more tile requests.
8. For point clouds, enable attenuation and eyeDomeLighting to fill gaps and add depth.
9. Keep enableCollision: false unless camera collision or CLAMP_TO_GROUND on tiles is needed.
10. Preload hidden tilesets with show: false and preloadWhenHidden: true.
11. Avoid translucent styles when possible -- they add rendering passes and disable optimizations.
12. Listen to tileFailed to log errors; call trimLoadedTiles() after large camera jumps.

See Also

• cesiumjs-custom-shader -- GLSL authoring for Cesium3DTileset.customShader and VoxelPrimitive.customShader (struct reference, feature IDs, metadata)
• cesiumjs-materials-shaders -- ImageBasedLighting, post-processing stages for tilesets
• cesiumjs-interaction -- Scene.pick, drillPick, ScreenSpaceEventHandler for feature selection
• cesiumjs-terrain-environment -- Globe, terrain providers, atmosphere, lighting, shadows