diff --git a/types/three/three-core.d.ts b/types/three/three-core.d.ts
index 5576a4b511..955eb45faf 100755
--- a/types/three/three-core.d.ts
+++ b/types/three/three-core.d.ts
@@ -3220,21 +3220,21 @@ export class Box3 {
     max: Vector3;
     min: Vector3;
 
-    set(min: Vector3, max: Vector3): Box3;
-    setFromArray(array: ArrayLike<number>): Box3;
-    setFromPoints(points: Vector3[]): Box3;
-    setFromCenterAndSize(center: Vector3, size: Vector3): Box3;
-    setFromObject(object: Object3D): Box3;
+    set(min: Vector3, max: Vector3): this;
+    setFromArray(array: ArrayLike<number>): this;
+    setFromPoints(points: Vector3[]): this;
+    setFromCenterAndSize(center: Vector3, size: Vector3): this;
+    setFromObject(object: Object3D): this;
     clone(): this;
     copy(box: this): this;
-    makeEmpty(): Box3;
+    makeEmpty(): this;
     isEmpty(): boolean;
     getCenter(target: Vector3): Vector3;
     getSize(target: Vector3): Vector3;
-    expandByPoint(point: Vector3): Box3;
-    expandByVector(vector: Vector3): Box3;
-    expandByScalar(scalar: number): Box3;
-    expandByObject(object: Object3D): Box3;
+    expandByPoint(point: Vector3): this;
+    expandByVector(vector: Vector3): this;
+    expandByScalar(scalar: number): this;
+    expandByObject(object: Object3D): this;
     containsPoint(point: Vector3): boolean;
     containsBox(box: Box3): boolean;
     getParameter(point: Vector3): Vector3;
@@ -3244,10 +3244,10 @@ export class Box3 {
     clampPoint(point: Vector3, target: Vector3): Vector3;
     distanceToPoint(point: Vector3): number;
     getBoundingSphere(target: Sphere): Sphere;
-    intersect(box: Box3): Box3;
-    union(box: Box3): Box3;
-    applyMatrix4(matrix: Matrix4): Box3;
-    translate(offset: Vector3): Box3;
+    intersect(box: Box3): this;
+    union(box: Box3): this;
+    applyMatrix4(matrix: Matrix4): this;
+    translate(offset: Vector3): this;
     equals(box: Box3): boolean;
     /**
      * @deprecated Use {@link Box3#isEmpty .isEmpty()} instead.