API
Babylon Lite API|
ArcRotateCamera

Interface ArcRotateCamera

ArcRotateCamera — orbits around a target point. Uses Babylon.js convention: left-handed, alpha=rotation around Y, beta=elevation. Plain data + methods. Does NOT know about the scene.

Push-based dirty tracking: alpha/beta/radius use Object.defineProperty, target uses ObservableVec3. Changes call wm.markLocalDirty() immediately.

Inertia follows the Babylon.js model: input handlers accumulate per-frame offsets (inertialAlphaOffset, etc.) which are applied and exponentially decayed each frame by the controls module.

interface ArcRotateCamera {
    alpha: number;
    angularSensibility: number;
    beta: number;
    children: SceneNode[];
    farPlane: number;
    fov: number;
    inertia: number;
    inertialAlphaOffset: number;
    inertialBetaOffset: number;
    inertialPanningX: number;
    inertialPanningY: number;
    inertialRadiusOffset: number;
    lowerAlphaLimit?: number;
    lowerBetaLimit?: number;
    lowerRadiusLimit?: number;
    name?: string;
    nearPlane: number;
    ortho?: OrthographicBounds | null;
    panningInertia: number;
    panningSensibility: number;
    parent: IWorldMatrixProvider | null;
    radius: number;
    target: Vec3;
    upperAlphaLimit?: number;
    upperBetaLimit?: number;
    upperRadiusLimit?: number;
    viewport?: NormalizedViewport;
    wheelPrecision: number;
    worldMatrix: Mat4;
    worldMatrixVersion: number;
}

Hierarchy (View Summary)

Index
alpha angularSensibility beta children farPlane fov inertia inertialAlphaOffset inertialBetaOffset inertialPanningX inertialPanningY inertialRadiusOffset lowerAlphaLimit? lowerBetaLimit? lowerRadiusLimit? name? nearPlane ortho? panningInertia panningSensibility parent radius target upperAlphaLimit? upperBetaLimit? upperRadiusLimit? viewport? wheelPrecision worldMatrix worldMatrixVersion
alpha: number
angularSensibility: number

Mouse-drag orbit sensitivity (HIGHER = slower rotation). Babylon default 1000.

beta: number
children: SceneNode[]
farPlane: number
fov: number
inertia: number

Inertia coefficient for rotation and zoom (0 = instant stop, 0.9 = default, 1 = no decay).

inertialAlphaOffset: number

Per-frame inertial offsets — accumulated by input, applied & decayed each frame.

inertialBetaOffset: number
inertialPanningX: number
inertialPanningY: number
inertialRadiusOffset: number
lowerAlphaLimit?: number

Optional orbit limits enforced by attachControl's per-frame loop. undefined means unbounded on that side. Set these via setCameraLimits so the current pose is clamped immediately (and inertia zeroed at the wall), avoiding any overshoot-then-snap jiggle. Angles are in radians.

lowerBetaLimit?: number
lowerRadiusLimit?: number
name?: string

Optional source/debug name. Imported glTF cameras use the glTF camera name, or camera{index} when the source definition is unnamed.

nearPlane: number
ortho?: OrthographicBounds | null

Live orthographic view-volume extents, installed by enableOrthographicCamera and mutable/animatable thereafter. Null or undefined means the camera projects perspectively through fov.

panningInertia: number

Inertia coefficient for panning (0 = instant stop, 0.9 = default).

panningSensibility: number

Right-drag panning sensitivity in pixels-per-unit (LOWER = faster pan). Babylon default 50.

parent: IWorldMatrixProvider | null
radius: number
target: Vec3
upperAlphaLimit?: number
upperBetaLimit?: number
upperRadiusLimit?: number
viewport?: NormalizedViewport
wheelPrecision: number

Wheel-zoom sensitivity (HIGHER = slower zoom). Babylon default 3.

worldMatrix: Mat4

World-space 4×4 column-major matrix. May trigger lazy recomputation.

worldMatrixVersion: number

Monotonically increasing counter — bumped each time worldMatrix recomputes. Children snapshot this value to detect when their parent has changed. Must never decrease: _cameraChangeKey sums it with the projection revision and relies on that to detect every change without aliasing.