Updated builds.

build/three.js

@@ -40125,47 +40125,19 @@
 
 		isInstancedBufferGeometry: true,
 
-		addGroup: function ( start, count, materialIndex ) {
-
-			this.groups.push( {
-
-				start: start,
-				count: count,
-				materialIndex: materialIndex
-
-			} );
-
-		},
-
 		copy: function ( source ) {
 
-			var index = source.index;
-
-			if ( index !== null ) {
-
-				this.setIndex( index.clone() );
-
-			}
-
-			var attributes = source.attributes;
-
-			for ( var name in attributes ) {
-
-				var attribute = attributes[ name ];
-				this.addAttribute( name, attribute.clone() );
-
-			}
+			BufferGeometry.prototype.copy.call( this, source );
 
-			var groups = source.groups;
+			this.maxInstancedCount = source.maxInstancedCount;
 
-			for ( var i = 0, l = groups.length; i < l; i ++ ) {
+			return this;
 
-				var group = groups[ i ];
-				this.addGroup( group.start, group.count, group.materialIndex );
+		},
 
-			}
+		clone: function () {
 
-			return this;
+			return new this.constructor().copy( this );
 
 		}
 

build/three.module.js

@@ -40119,47 +40119,19 @@ InstancedBufferGeometry.prototype = Object.assign( Object.create( BufferGeometry
 
 	isInstancedBufferGeometry: true,
 
-	addGroup: function ( start, count, materialIndex ) {
-
-		this.groups.push( {
-
-			start: start,
-			count: count,
-			materialIndex: materialIndex
-
-		} );
-
-	},
-
 	copy: function ( source ) {
 
-		var index = source.index;
-
-		if ( index !== null ) {
-
-			this.setIndex( index.clone() );
-
-		}
-
-		var attributes = source.attributes;
-
-		for ( var name in attributes ) {
-
-			var attribute = attributes[ name ];
-			this.addAttribute( name, attribute.clone() );
-
-		}
+		BufferGeometry.prototype.copy.call( this, source );
 
-		var groups = source.groups;
+		this.maxInstancedCount = source.maxInstancedCount;
 
-		for ( var i = 0, l = groups.length; i < l; i ++ ) {
+		return this;
 
-			var group = groups[ i ];
-			this.addGroup( group.start, group.count, group.materialIndex );
+	},
 
-		}
+	clone: function () {
 
-		return this;
+		return new this.constructor().copy( this );
 
 	}