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Raycaster

This class is designed to assist with raycasting. Raycasting is used for mouse picking (working out what objects in the 3d space the mouse is over) amongst other things.

Code Example​

const raycaster = new THREE.Raycaster(); const pointer = new THREE.Vector2();
function onPointerMove( event ) { // calculate pointer position in normalized
device coordinates // (-1 to +1) for both components pointer.x = (
event.clientX / window.innerWidth ) * 2 - 1; pointer.y = - ( event.clientY /
window.innerHeight ) * 2 + 1; } function render() { // update the picking ray
with the camera and pointer position raycaster.setFromCamera( pointer, camera
); // calculate objects intersecting the picking ray const intersects =
raycaster.intersectObjects( scene.children ); for ( let i = 0; i <
intersects.length; i ++ ) { intersects[ i ].object.material.color.set(
0xff0000 ); } renderer.render( scene, camera ); } window.addEventListener(
'pointermove', onPointerMove ); window.requestAnimationFrame(render);

Examples​

[example:webgl_interactive_cubes Raycasting to a Mesh]
[example:webgl_interactive_cubes_ortho Raycasting to a Mesh in using an OrthographicCamera]
[example:webgl_interactive_buffergeometry Raycasting to a Mesh with BufferGeometry]
[example:webgl_instancing_raycast Raycasting to a InstancedMesh]
[example:webgl_interactive_lines Raycasting to a Line]
[example:webgl_interactive_raycasting_points Raycasting to Points]
[example:webgl_geometry_terrain_raycast Terrain raycasting]
[example:webgl_interactive_voxelpainter Raycasting to paint voxels]
[example:webgl_raycaster_texture Raycast to a Texture]

Constructor​

Raycaster​

function Raycaster( origin: Vector3, direction: Vector3, near: Float, far:
Float ): void;

origin — The origin vector where the ray casts from.
direction — The direction vector that gives direction to the ray. Should be normalized.
near — All results returned are further away than near. Near can't be negative. Default value is 0.
far — All results returned are closer than far. Far can't be lower than near. Default value is Infinity.

This creates a new raycaster object.

Properties​

far​

far: Float;

The far factor of the raycaster. This value indicates which objects can be discarded based on the distance. This value shouldn't be negative and should be larger than the near property.

near​

near: Float;

The near factor of the raycaster. This value indicates which objects can be discarded based on the distance. This value shouldn't be negative and should be smaller than the far property.

camera​

camera: Camera;

The camera to use when raycasting against view-dependent objects such as billboarded objects like Sprites. This field can be set manually or is set when calling "setFromCamera". Defaults to null.

layers​

layers: Layers;

Used by Raycaster to selectively ignore 3D objects when performing intersection tests. The following code example ensures that only 3D objects on layer 1 will be honored by the instance of Raycaster.

raycaster.layers.set( 1 ); object.layers.enable( 1 );

params​

params: Object;

An object with the following properties:

{ Mesh: {}, Line: { threshold: 1 }, LOD: {}, Points: { threshold: 1 }, Sprite:
{} }

Where threshold is the precision of the raycaster when intersecting objects, in world units.

ray​

ray: Ray;

The [Page:Ray] used for the raycasting.

Methods​

set​

function set( origin: Vector3, direction: Vector3 ): undefined;

origin — The origin vector where the ray casts from.
direction — The normalized direction vector that gives direction to the ray.

Updates the ray with a new origin and direction. Please note that this method only copies the values from the arguments.

setFromCamera​

function setFromCamera( coords: Vector2, camera: Camera ): undefined;

coords — 2D coordinates of the mouse, in normalized device coordinates (NDC)---X and Y components should be between -1 and 1.
camera — camera from which the ray should originate

Updates the ray with a new origin and direction.

intersectObject​

function intersectObject( object: Object3D, recursive: Boolean,
optionalTarget: Array ): Array;

object — The object to check for intersection with the ray.
recursive — If true, it also checks all descendants. Otherwise it only checks intersection with the object. Default is true.
optionalTarget — (optional) target to set the result. Otherwise a new Array is instantiated. If set, you must clear this array prior to each call (i.e., array.length = 0;).

Checks all intersection between the ray and the object with or without the descendants. Intersections are returned sorted by distance, closest first. An array of intersections is returned...

[ { distance, point, face, faceIndex, object }, ... ]

distance – distance between the origin of the ray and the intersection
point – point of intersection, in world coordinates
face – intersected face
faceIndex – index of the intersected face
object – the intersected object
uv - U,V coordinates at point of intersection
uv1 - Second set of U,V coordinates at point of intersection
normal - interpolated normal vector at point of intersection
instanceId – The index number of the instance where the ray intersects the InstancedMesh

Raycaster delegates to the raycast method of the passed object, when evaluating whether the ray intersects the object or not. This allows meshes to respond differently to ray casting than lines and pointclouds.

Note that for meshes, faces must be pointed towards the origin of the .ray in order to be detected; intersections of the ray passing through the back of a face will not be detected. To raycast against both faces of an object, you'll want to set the material's side property to THREE.DoubleSide.

intersectObjects​

function intersectObjects( objects: Array, recursive: Boolean, optionalTarget:
Array ): Array;

objects — The objects to check for intersection with the ray.
recursive — If true, it also checks all descendants of the objects. Otherwise it only checks intersection with the objects. Default is true.
optionalTarget — (optional) target to set the result. Otherwise a new Array is instantiated. If set, you must clear this array prior to each call (i.e., array.length = 0;).

Checks all intersection between the ray and the objects with or without the descendants. Intersections are returned sorted by distance, closest first. Intersections are of the same form as those returned by .intersectObject.

Source​

src/core/Raycaster.js