Orbit

Defines a spherical orbit around a pivot — a movable ring that other nodes can be made to revolve along.

Declarative element: <sk-orbit>

Not on the sk.* global — construct via the declarative element or a module import.

Remarks

This is a SceneNode (a VisualizableSceneNode), not a constraint. Its job is to hold orbit parameters: its world position is the pivot, and its radius/azimuth/elevation describe a position on a sphere around that pivot. It does NOT move anything by itself — a separate sk-orbit-constraint reads this node and drives the constrained node's position (and orientation). This is the same split as SpatialField + sk-field-constraint: one node carries the data, another applies the effect.

Why a node. Because the pivot is a real scene node, you get animation for free (keyframe azimuth and the orbit position sweeps around, carrying whatever an sk-orbit-constraint binds to it), composition for free (parent it under a moving platform for an inherited pivot), and an optional on-canvas visualization.

Key attributes. radius is the pivot-to-orbit distance. azimuth is the angle around the +Y (up) axis, measured from +Z, positive turning toward +X. elevation is the angle above the XZ plane (positive toward +Y). All three are animatable. orient-toward-pivot also faces the riding node's orientation-axis back at the pivot. visualize draws the orbit ring and interactive markers.

Constructor

constructor(config?: { radius?: number; azimuth?: number; elevation?: number; minRadius?: number; orientTowardPivot?: boolean; orientationAxis?: AxisOrientation; visualize?: boolean; interactiveControls?: boolean; visualizationMarkerSize?: number; visualizationColor?: string; visualizationZeroWeightColor?: string; visualizationSplineThickness?: number; visualizationSplineOccludedOpacity?: number; visualizationMarkerOpacity?: number; id?: string; x?: number; y?: number; z?: number; h?: number; p?: number; b?: number; quaternion?: Quaternion; sx?: number; sy?: number; sz?: number; s?: number; class?: string; style?: string })

Inherited from: VisualizableSceneNode, SceneNode, SkenraAnimatable — see those pages for inherited members.

Properties

Config Properties

Other Properties

Methods

Example

// Create an orbit node (defines the orbit)
const orbitNode = new Orbit({ id: 'camera-orbit',
    radius: 15,
    azimuth: Math.PI / 4,
    elevation: Math.PI / 6,
    orientTowardPivot: true,
    orientationAxis: '-z',
    visualize: true,
});
scene.appendChild(orbitNode);

// Constrain camera to follow the orbit
camera.constrain('orbit', { source: orbitNode });

// Animate the orbit
orbitNode.animate([
    { offset: 0, azimuth: 0 },
    { offset: 1, azimuth: Math.PI * 2 },
], { duration: 10000, iterations: Infinity, id: 'spin' });

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