import { Vector3D } from './ZenSpace3DTypes';
/** Earth's mean radius in km. */
export declare const EARTH_RADIUS_KM = 6371;
/** Degrees → radians. */
export declare const DEG_TO_RAD: number;
/** Radians → degrees. */
export declare const RAD_TO_DEG: number;
/** Earth radius in scene units (Three.js render space). */
export declare const SCENE_EARTH_RADIUS = 3000;
/** Conversion factor: 1 km → scene units. */
export declare const KM_TO_SCENE: number;
/**
 * Convert lat/lon/alt to a Cartesian point in scene space.
 *
 * Result is in *render units* (scaled by `KM_TO_SCENE`), suitable for
 * direct use in the Three.js scene graph. For ECI→ECEF on the Cesium
 * backend, use `Cesium.Transforms.computeTemeToPseudoFixedMatrix`.
 *
 * @param lat        Latitude in degrees.
 * @param lon        Longitude in degrees.
 * @param altKm      Altitude above Earth surface in km (default 0).
 * @param earthRadius Scene radius for Earth (default `SCENE_EARTH_RADIUS`).
 */
export declare function latLonAltToCartesian(lat: number, lon: number, altKm?: number, earthRadius?: number): Vector3D;
/** Cubic ease-out curve, used by camera fly-to animations. */
export declare function easeOutCubic(t: number): number;