diff --git a/types/three/index.d.ts b/types/three/index.d.ts
index b8c5b5669f..17156bed94 100644
--- a/types/three/index.d.ts
+++ b/types/three/index.d.ts
@@ -25,5 +25,7 @@ export * from "./three-trackballcontrols";
 export * from "./three-transformcontrols";
 export * from "./three-vrcontrols";
 export * from "./three-vreffect";
+export * from "./three-objloader";
+export * from "./three-mtlloader";
 
-export as namespace THREE;
\ No newline at end of file
+export as namespace THREE;
diff --git a/types/three/three-core.d.ts b/types/three/three-core.d.ts
index 5679c4e8c7..ea0e6f917c 100644
--- a/types/three/three-core.d.ts
+++ b/types/three/three-core.d.ts
@@ -1355,7 +1355,7 @@ export class Geometry extends EventDispatcher {
      */
     computeBoundingSphere(): void;
 
-    merge(geometry: Geometry, matrix: Matrix, materialIndexOffset?: number): void;
+    merge(geometry: Geometry, matrix?: Matrix, materialIndexOffset?: number): void;
 
     mergeMesh(mesh: Mesh): void;
 
@@ -1605,6 +1605,18 @@ export class Object3D extends EventDispatcher {
      */
     userData: any;
 
+    /**
+     * Calls before rendering object
+     */
+    onBeforeRender: (renderer: THREE.WebGLRenderer, scene: THREE.Scene, camera: THREE.Camera, geometry: THREE.Geometry | THREE.BufferGeometry,
+                     material: THREE.Material, group: THREE.Group) => any;
+
+    /**
+     * Calls after rendering object
+     */
+    onAfterRender: (renderer: THREE.WebGLRenderer, scene: THREE.Scene, camera: THREE.Camera, geometry: THREE.Geometry | THREE.BufferGeometry,
+                    material: THREE.Material, group: THREE.Group) => any;
+
     /**
      *
      */
@@ -1706,7 +1718,7 @@ export class Object3D extends EventDispatcher {
     /**
      * Adds object as child of this object.
      */
-    add(object: Object3D): void;
+    add(...object: Object3D[]): void;
 
     /**
      * Removes object as child of this object.
@@ -2796,9 +2808,12 @@ export class MeshPhysicalMaterial extends MeshStandardMaterial {
 export class MultiMaterial extends Material {
     constructor(materials?: Material[]);
 
+    isMultiMaterial: true;
+
     materials: Material[];
 
     toJSON(meta: any): any;
+
 }
 
 /**
diff --git a/types/three/three-examples.d.ts b/types/three/three-examples.d.ts
index d416757b00..67efcc566a 100644
--- a/types/three/three-examples.d.ts
+++ b/types/three/three-examples.d.ts
@@ -3,7 +3,6 @@
 import {EventDispatcher, Shader} from "./three-core";
 
 export var AWDLoader: any;
-export var OBJLoader: any;
 export var OBJLoader2: any;
 export var STLLoader: any;
 export var FlyControls: any;
diff --git a/types/three/three-mtlloader.d.ts b/types/three/three-mtlloader.d.ts
new file mode 100644
index 0000000000..5113d67df2
--- /dev/null
+++ b/types/three/three-mtlloader.d.ts
@@ -0,0 +1,52 @@
+
+import {Material} from "./three-core";
+import {LoadingManager} from "./three-core";
+import {EventDispatcher} from "./three-core";
+import {BufferGeometry} from "./three-core";
+import {Texture} from "./three-core";
+
+export class MTLLoader extends EventDispatcher {
+
+    constructor(manager?: LoadingManager);
+    manager: LoadingManager;
+    materialOptions: {};
+    materials: Material[];
+    path: string;
+    texturePath: string;
+    crossOrigin: boolean;
+
+    load(url: string, onLoad: (materialCreator: MaterialCreator) => void, onProgress?: (event: any) => void, onError?: (event: any) => void): void;
+    parse(text: string) : MaterialCreator;
+    setPath(path: string) : void;
+    setTexturePath(path: string) : void;
+    setBaseUrl(path: string) : void;
+    setCrossOrigin(value: boolean) : void;
+    setMaterialOptions(value: any) : void;
+}
+
+export class MaterialCreator {
+
+    constructor(baseUrl?: string, options?: any);
+
+    baseUrl : string;
+    options : any;
+    materialsInfo : any;
+    materials : any;
+    materialsArray : Material[];
+    nameLookup : any;
+    side : number;
+    wrap : number;
+
+    setCrossOrigin( value: boolean ) : void;
+    setManager( value: any ) : void;
+    setMaterials( materialsInfo: any ) : void;
+    convert( materialsInfo: any ) : any;
+    preload() : void;
+    getIndex( materialName: string ) : Material;
+    getAsArray() : Material[];
+    create( materialName: string ) : Material;
+    createMaterial_( materialName: string ) : Material;
+    getTextureParams( value: string, matParams: any ) : any;
+    loadTexture(url: string, mapping: any, onLoad: (bufferGeometry: BufferGeometry) => void, onProgress?: (event: any) => void, onError?: (event: any) => void): Texture;
+
+}
diff --git a/types/three/three-objloader.d.ts b/types/three/three-objloader.d.ts
new file mode 100644
index 0000000000..25a3adf93f
--- /dev/null
+++ b/types/three/three-objloader.d.ts
@@ -0,0 +1,21 @@
+
+import {Material} from "./three-core";
+import {LoadingManager} from "./three-core";
+import {Group} from "./three-core";
+import {MaterialCreator} from "./three-mtlloader";
+
+export class OBJLoader {
+
+    constructor(manager?: LoadingManager);
+    manager: LoadingManager;
+    regexp: any;
+    materials: Material[];
+    path: string;
+
+    load(url: string, onLoad: (group: Group) => void, onProgress?: (event: any) => void, onError?: (event: any) => void): void;
+    parse(data: string) : Group;
+    setPath(value: string) : void;
+    setMaterials(materials: MaterialCreator) : void;
+    _createParserState() : any;
+
+}