public ObjMesh(ObjGroup owner)
 {
     Owner           = owner;
     PositionFaces   = new List<Face>();
     NormalFaces     = new List<Face>();
     TexCoordFaces   = new List<Face>();
 }
        private ObjGroup NewGroup()
        {
            if(CurrentGroup != null && CurrentGroup.IsEmpty)
                return CurrentGroup;

            CurrentGroup    = new ObjGroup(this);

            Groups.Add(CurrentGroup);

            return CurrentGroup;
        }