From cesiumjs-skills
Provides usage patterns, architecture, and code examples for CesiumJS Primitive, GeometryInstance, Appearance, and batching. Use when rendering performant static/vector geometry, loading GeoJSON without entities, or creating custom batched shapes.
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/cesiumjs-skills:cesiumjs-primitivesThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
> **Applies to:** CesiumJS v1.142+ (ES module imports, `??` instead of `defaultValue`)
Applies to: CesiumJS v1.142+ (ES module imports,
??instead ofdefaultValue)
The Primitive API is the low-level rendering layer beneath the Entity API, trading convenience for performance.
Core formula: Primitive = GeometryInstance[] + Appearance
Primitives are immutable after first render -- geometry cannot change, but per-instance attributes update via primitive.getGeometryInstanceAttributes(id).
import {
Viewer, Primitive, GeometryInstance, EllipseGeometry,
EllipsoidSurfaceAppearance, Material, Cartesian3, Math as CesiumMath,
} from "cesium";
const viewer = new Viewer("cesiumContainer");
const scene = viewer.scene;
const primitive = scene.primitives.add(new Primitive({
geometryInstances: new GeometryInstance({
geometry: new EllipseGeometry({
center: Cartesian3.fromDegrees(-100.0, 40.0),
semiMinorAxis: 250000.0,
semiMajorAxis: 400000.0,
rotation: CesiumMath.PI_OVER_FOUR,
vertexFormat: EllipsoidSurfaceAppearance.VERTEX_FORMAT, // must match appearance
}),
id: "myEllipse", // returned by Scene.pick()
}),
appearance: new EllipsoidSurfaceAppearance({ material: Material.fromType("Stripe") }),
}));
| Option | Default | Purpose |
|---|---|---|
geometryInstances | -- | Single instance or array |
appearance | -- | Shading (Appearance subclass) |
show | true | Toggle visibility |
modelMatrix | Matrix4.IDENTITY | Transform all instances |
asynchronous | true | Build geometry on web worker |
releaseGeometryInstances | true | Free geometry after GPU upload |
allowPicking | true | false saves GPU memory |
shadows | ShadowMode.DISABLED | Cast/receive shadows |
All instances in one Primitive share a single draw call.
import {
Primitive, GeometryInstance, RectangleGeometry, EllipseGeometry,
PerInstanceColorAppearance, ColorGeometryInstanceAttribute,
Cartesian3, Rectangle, Color,
} from "cesium";
scene.primitives.add(new Primitive({
geometryInstances: [
new GeometryInstance({
geometry: new RectangleGeometry({
rectangle: Rectangle.fromDegrees(-140, 30, -100, 40),
vertexFormat: PerInstanceColorAppearance.VERTEX_FORMAT,
}),
id: "rect",
attributes: { color: ColorGeometryInstanceAttribute.fromColor(Color.RED.withAlpha(0.5)) },
}),
new GeometryInstance({
geometry: new EllipseGeometry({
center: Cartesian3.fromDegrees(-80, 35),
semiMinorAxis: 200000.0,
semiMajorAxis: 300000.0,
vertexFormat: PerInstanceColorAppearance.VERTEX_FORMAT,
}),
id: "ellipse",
attributes: { color: ColorGeometryInstanceAttribute.fromColor(Color.BLUE.withAlpha(0.5)) },
}),
],
appearance: new PerInstanceColorAppearance(),
}));
import { ColorGeometryInstanceAttribute, ShowGeometryInstanceAttribute } from "cesium";
// Wait for async geometry compilation
const removeListener = scene.postRender.addEventListener(() => {
if (!primitive.ready) return;
const attrs = primitive.getGeometryInstanceAttributes("rect");
attrs.color = ColorGeometryInstanceAttribute.toValue(Color.YELLOW);
attrs.show = ShowGeometryInstanceAttribute.toValue(true);
removeListener();
});
Nestable container -- scene.primitives is itself a PrimitiveCollection.
import { PrimitiveCollection, BillboardCollection, LabelCollection } from "cesium";
const group = new PrimitiveCollection();
group.add(new BillboardCollection());
group.add(new LabelCollection());
scene.primitives.add(group);
group.show = false; // toggle all children
| Need | Use |
|---|---|
| Entity lifecycle, clustering, per-entity styling, time-dynamic values | GeoJsonDataSource in cesiumjs-entities |
| One large GeoJSON object with low overhead and primitive-level performance | GeoJsonPrimitive in this skill |
| Tiled vector data, 3D Tiles LOD, metadata styling, feature picking | MVTDataProvider in cesiumjs-3d-tiles |
| Fully manual high-throughput point/polyline/polygon buffers | BufferPointCollection, BufferPolylineCollection, BufferPolygonCollection |
Use BufferPointCollection, BufferPolylineCollection, and BufferPolygonCollection
for very large vector datasets where Entity/DataSource overhead is too high. These
APIs were introduced in 1.140 (#13212) and refined through 1.142; they are
experimental and use flyweight primitive objects: reuse one BufferPoint,
BufferPolyline, or BufferPolygon when adding or iterating thousands of items.
import {
BlendOption,
BoundingSphere,
BufferPoint,
BufferPointCollection,
BufferPointMaterial,
Cartesian3,
Color,
} from "cesium";
const positions = [
Cartesian3.fromDegrees(-75.16, 39.95),
Cartesian3.fromDegrees(-73.98, 40.75),
];
const points = scene.primitives.add(new BufferPointCollection({
primitiveCountMax: positions.length,
allowPicking: true,
blendOption: BlendOption.TRANSLUCENT,
boundingVolume: BoundingSphere.fromPoints(positions), // world space in 1.142+
}));
const point = new BufferPoint();
const material = new BufferPointMaterial({
color: Color.CYAN.withAlpha(0.65),
outlineColor: Color.WHITE.withAlpha(0.9),
outlineWidth: 2,
size: 10,
});
positions.forEach((position, featureId) => {
points.add({
position,
featureId,
material,
}, point);
});
const picked = scene.pick(windowPosition);
if (picked?.collection === points) {
console.log(picked.index, picked.primitive.featureId);
}
Breaking change (1.141, #13448):
BufferPrimitiveCollection.modelMatrix,boundingVolume, andboundingVolumeWCare now readonly -- you may mutate the object in place, but reassigning the property (collection.modelMatrix = ...) throws. Update the existing matrix/volume instead of swapping in a new one.
1.142 notes:
boundingVolume is now world-space, not local/model-space. If you provide it manually, include the collection modelMatrix transform yourself.boundingVolume skips automatic recomputation; this helps large animated collections but makes you responsible for keeping the volume valid.blendOption is supported on all three buffer collections and enables alpha from BufferPrimitiveMaterial#color; BufferPointCollection also honors outlineColor.alpha.BlendOption.OPAQUE only when every material is fully opaque; use TRANSLUCENT or mixed blending when alpha varies.GeoJsonPrimitive loads GeoJSON directly into buffer primitive collections,
bypassing GeoJsonDataSource and the Entity layer. Prefer it for large static
or bulk-updated vector datasets. Keep using GeoJsonDataSource when you need
Entity conveniences, time-dynamic properties, clustering, or DataSource lifecycle
integration.
import { GeoJsonPrimitive } from "cesium";
const counties = await GeoJsonPrimitive.fromUrl("/data/counties.geojson", {
allowPicking: true,
});
scene.primitives.add(counties);
console.log(counties.featureCount);
console.log(counties.points); // BufferPointCollection | undefined
console.log(counties.polylines); // BufferPolylineCollection | undefined
console.log(counties.polygons); // BufferPolygonCollection | undefined
// Picking returns the GeoJsonPrimitive pick object, including source properties.
const picked = scene.pick(windowPosition);
if (picked?.parentPrimitive === counties) {
const featureId = picked.primitive.featureId;
console.log(counties.getId(featureId));
console.log(counties.getProperties(featureId));
}
GeoJsonPrimitive.fromGeoJson(parsedObject) is available when the GeoJSON is
already in memory. Source feature IDs are exposed through ids/getId(), and
source properties through properties/getProperties().
All geometries take shape parameters and a vertexFormat matching the Appearance. Most have a paired *OutlineGeometry. Outlines require a separate Primitive.
import {
Primitive, GeometryInstance, PolygonGeometry, PolygonOutlineGeometry,
PolygonHierarchy, PerInstanceColorAppearance, ColorGeometryInstanceAttribute,
Cartesian3, Color,
} from "cesium";
const positions = Cartesian3.fromDegreesArray([-115, 37, -115, 32, -107, 33, -102, 35]);
// Fill primitive
scene.primitives.add(new Primitive({
geometryInstances: new GeometryInstance({
geometry: new PolygonGeometry({
polygonHierarchy: new PolygonHierarchy(positions),
vertexFormat: PerInstanceColorAppearance.VERTEX_FORMAT,
}),
attributes: { color: ColorGeometryInstanceAttribute.fromColor(Color.CYAN.withAlpha(0.5)) },
}),
appearance: new PerInstanceColorAppearance(),
}));
// Outline primitive (separate draw call)
scene.primitives.add(new Primitive({
geometryInstances: new GeometryInstance({
geometry: new PolygonOutlineGeometry({ polygonHierarchy: new PolygonHierarchy(positions) }),
attributes: { color: ColorGeometryInstanceAttribute.fromColor(Color.WHITE) },
}),
appearance: new PerInstanceColorAppearance({ flat: true }),
}));
Every XxxGeometry has a matching XxxOutlineGeometry unless noted.
Surface (work with GroundPrimitive): CircleGeometry, CorridorGeometry, EllipseGeometry, PolygonGeometry, RectangleGeometry.
Volume (need modelMatrix): BoxGeometry (fromDimensions()), CylinderGeometry (cone when topRadius != bottomRadius), EllipsoidGeometry, SphereGeometry, FrustumGeometry, PlaneGeometry.
Path: CorridorGeometry (buffered path), PolylineVolumeGeometry (2D shape extruded along path), WallGeometry (vertical curtain).
Polygon: PolygonGeometry (holes via PolygonHierarchy), CoplanarPolygonGeometry (non-Earth-surface).
Line (no outline): PolylineGeometry (pixel-width), SimplePolylineGeometry (1px), GroundPolylineGeometry (GroundPolylinePrimitive only).
Box, Ellipsoid, Cylinder, and Frustum need a modelMatrix on the GeometryInstance.
import { GeometryInstance, BoxGeometry, PerInstanceColorAppearance,
ColorGeometryInstanceAttribute, Cartesian3, Matrix4, Transforms, Color } from "cesium";
const modelMatrix = Matrix4.multiplyByTranslation(
Transforms.eastNorthUpToFixedFrame(Cartesian3.fromDegrees(-105, 40)),
new Cartesian3(0, 0, 250000), new Matrix4(),
);
new GeometryInstance({
geometry: BoxGeometry.fromDimensions({
dimensions: new Cartesian3(400000, 300000, 500000),
vertexFormat: PerInstanceColorAppearance.VERTEX_FORMAT,
}),
modelMatrix,
id: "floatingBox",
attributes: { color: ColorGeometryInstanceAttribute.fromColor(Color.CORAL) },
});
| Appearance | Use Case | Material? |
|---|---|---|
PerInstanceColorAppearance | Per-instance color | No |
MaterialAppearance | Arbitrary geometry + Material | Yes |
EllipsoidSurfaceAppearance | Surface geometry + Material (fewer attrs) | Yes |
PolylineColorAppearance | Per-instance color polylines | No |
PolylineMaterialAppearance | Polylines with Material | Yes |
DebugAppearance | Visualize vertex attributes | No |
Appearance | Base class / custom shaders | Optional |
The geometry vertexFormat must match the appearance. Use the appearance's static VERTEX_FORMAT. For PerInstanceColorAppearance without lighting, use FLAT_VERTEX_FORMAT.
import { Primitive, GeometryInstance, WallGeometry, MaterialAppearance, Material, Cartesian3 } from "cesium";
scene.primitives.add(new Primitive({
geometryInstances: new GeometryInstance({
geometry: new WallGeometry({
positions: Cartesian3.fromDegreesArrayHeights([-115, 44, 200000, -110, 44, 200000, -105, 44, 200000]),
vertexFormat: MaterialAppearance.MaterialSupport.TEXTURED.vertexFormat,
}),
}),
appearance: new MaterialAppearance({
material: Material.fromType("Checkerboard"),
faceForward: true, // shade both sides
}),
}));
Drapes geometry onto terrain/3D Tiles. Supported: CircleGeometry, CorridorGeometry, EllipseGeometry, PolygonGeometry, RectangleGeometry.
import { GroundPrimitive, GeometryInstance, PolygonGeometry, PolygonHierarchy,
ColorGeometryInstanceAttribute, ClassificationType, Cartesian3, Color } from "cesium";
scene.groundPrimitives.add(new GroundPrimitive({
geometryInstances: new GeometryInstance({
geometry: new PolygonGeometry({
polygonHierarchy: new PolygonHierarchy(
Cartesian3.fromDegreesArray([-112, 36, -112, 36.1, -111.9, 36.1]),
),
}),
id: "groundPolygon",
attributes: { color: ColorGeometryInstanceAttribute.fromColor(Color.RED.withAlpha(0.5)) },
}),
classificationType: ClassificationType.TERRAIN, // TERRAIN, CESIUM_3D_TILE, or BOTH
}));
import { GroundPolylinePrimitive, GeometryInstance, GroundPolylineGeometry,
PolylineColorAppearance, ColorGeometryInstanceAttribute, Cartesian3, Color } from "cesium";
scene.groundPrimitives.add(new GroundPolylinePrimitive({
geometryInstances: new GeometryInstance({
geometry: new GroundPolylineGeometry({
positions: Cartesian3.fromDegreesArray([-112.13, 36.05, -112.09, 36.10, -112.13, 36.17]),
width: 4.0,
loop: true,
}),
attributes: { color: ColorGeometryInstanceAttribute.fromColor(Color.LIME.withAlpha(0.7)) },
}),
appearance: new PolylineColorAppearance(),
}));
Highlights volumes classifying terrain or 3D Tiles. Valid: BoxGeometry, CylinderGeometry, EllipsoidGeometry, PolylineVolumeGeometry, SphereGeometry, plus extruded surface geometries.
import { ClassificationPrimitive, GeometryInstance, BoxGeometry, PerInstanceColorAppearance,
ColorGeometryInstanceAttribute, ClassificationType, Cartesian3, Transforms, Color } from "cesium";
scene.primitives.add(new ClassificationPrimitive({
geometryInstances: new GeometryInstance({
geometry: BoxGeometry.fromDimensions({
dimensions: new Cartesian3(100, 100, 50),
vertexFormat: PerInstanceColorAppearance.VERTEX_FORMAT,
}),
modelMatrix: Transforms.eastNorthUpToFixedFrame(Cartesian3.fromDegrees(-75.59, 40.04, 25)),
attributes: { color: ColorGeometryInstanceAttribute.fromColor(Color.YELLOW.withAlpha(0.5)) },
}),
classificationType: ClassificationType.BOTH,
}));
GPU-efficient viewport-aligned images -- far more performant than entities at scale.
Breaking change (1.140, #13253):
BillboardCollectionandLabelCollectionnow require WebGL 2, or WebGL 1 withANGLE_instanced_arraysandMAX_VERTEX_TEXTURE_IMAGE_UNITS > 0. On unsupported devices they no longer render -- gate onscene.context.webgl2(or feature-detect the extension) if you still target legacy WebGL 1 hardware.
import { BillboardCollection, Cartesian3, Color, NearFarScalar,
HeightReference, HorizontalOrigin, VerticalOrigin } from "cesium";
const billboards = scene.primitives.add(new BillboardCollection({ scene }));
const b = billboards.add({
position: Cartesian3.fromDegrees(-75.59, 40.04),
image: "marker.png",
horizontalOrigin: HorizontalOrigin.CENTER,
verticalOrigin: VerticalOrigin.BOTTOM,
heightReference: HeightReference.CLAMP_TO_GROUND,
scaleByDistance: new NearFarScalar(1000, 1.5, 1e7, 0.3),
});
b.position = Cartesian3.fromDegrees(-75.60, 40.05); // update dynamically
billboards.remove(b);
import { LabelCollection, Cartesian3, Cartesian2, Color, LabelStyle, VerticalOrigin } from "cesium";
const labels = scene.primitives.add(new LabelCollection({ scene }));
labels.add({
position: Cartesian3.fromDegrees(-75.59, 40.04, 300),
text: "Philadelphia",
font: "16px sans-serif",
fillColor: Color.WHITE,
outlineColor: Color.BLACK,
outlineWidth: 2,
style: LabelStyle.FILL_AND_OUTLINE,
verticalOrigin: VerticalOrigin.BOTTOM,
pixelOffset: new Cartesian2(0, -10),
});
import { PointPrimitiveCollection, Cartesian3, Color, NearFarScalar } from "cesium";
const points = scene.primitives.add(new PointPrimitiveCollection());
points.add({
position: Cartesian3.fromDegrees(-75.59, 40.04),
pixelSize: 10,
color: Color.YELLOW,
outlineColor: Color.BLACK,
outlineWidth: 2,
scaleByDistance: new NearFarScalar(1000, 1.0, 1e7, 0.1),
});
import { CloudCollection, PolylineCollection, Cartesian3, Cartesian2, Color, Material } from "cesium";
// Procedural cumulus clouds
const clouds = scene.primitives.add(new CloudCollection());
clouds.add({
position: Cartesian3.fromDegrees(-75.59, 40.04, 1500),
scale: new Cartesian2(40, 12),
maximumSize: new Cartesian3(40, 12, 15),
slice: 0.36,
});
// Low-level polyline collection
const polylines = scene.primitives.add(new PolylineCollection());
polylines.add({
positions: Cartesian3.fromDegreesArray([-75, 40, -70, 42, -65, 38]),
width: 3.0,
material: Material.fromType("Color", { color: Color.AQUA }),
});
import { Primitive, GeometryInstance, PolylineGeometry, PolylineColorAppearance,
ColorGeometryInstanceAttribute, Cartesian3, Color, ArcType } from "cesium";
scene.primitives.add(new Primitive({
geometryInstances: new GeometryInstance({
geometry: new PolylineGeometry({
positions: Cartesian3.fromDegreesArray([0, 0, 5, 0]),
width: 10.0,
vertexFormat: PolylineColorAppearance.VERTEX_FORMAT,
arcType: ArcType.GEODESIC, // GEODESIC, RHUMB, or NONE
}),
attributes: { color: ColorGeometryInstanceAttribute.fromColor(Color.WHITE) },
}),
appearance: new PolylineColorAppearance({ translucent: false }),
}));
| Enum | Values | Used By |
|---|---|---|
ArcType | GEODESIC, RHUMB, NONE | PolylineGeometry, PolygonGeometry |
CornerType | ROUNDED, MITERED, BEVELED | CorridorGeometry, PolylineVolumeGeometry |
ClassificationType | TERRAIN, CESIUM_3D_TILE, BOTH | GroundPrimitive, ClassificationPrimitive |
PrimitiveType | POINTS, LINES, TRIANGLES, etc. | Low-level Geometry |
CloudType | CUMULUS | CloudCollection |
PerInstanceColorAppearance when each instance only needs a distinct color.flat: true on PerInstanceColorAppearance when lighting is unneeded; uses FLAT_VERTEX_FORMAT.allowPicking: false on Primitives that will never be picked to save GPU memory.asynchronous: true (default). Check primitive.ready before accessing instance attributes.BlendOption.OPAQUE on BillboardCollection/PointPrimitiveCollection when all items are opaque (up to 2x gain).heightReference.vertexFormat exactly to the appearance to skip unused vertex attribute computation.EllipsoidSurfaceAppearance over MaterialAppearance for surface geometry -- fewer vertex attributes.MVTDataProvider for tiled vector data as runtime 3D Tiles.npx claudepluginhub cesiumgs/cesiumjs-skills --plugin cesiumjs-skillsCovers CesiumJS Entity API: adding points, billboards, labels, models, polygons, and polylines; loading GeoJSON/KML/CZML/GPX data; managing EntityCollections and DataSources.
Creates and optimizes Three.js geometry: built-in shapes, custom BufferGeometry, vertices, and instanced rendering.
Guides users through first interactions with the Cesium 3D globe via MCP tools, including camera navigation, entity creation, and layer loading.