copy( frustum ) {

		const planes = this.planes;

		for ( let i = 0; i < 6; i ++ ) {

			planes[ i ].copy( frustum.planes[ i ] );

		}

		return this;

	}
Copies the values of the given frustum to this instance.

@param {Frustum} frustum - The frustum to copy.
@return {Frustum} A reference to this frustum.