A method that includes coextruding two or more thermoplastic resin streams
through a profiled die plate, which die plate is shaped to form a
nonplanar film (three dimensional) preferably with a regularly
oscillating peak and valley structure that oscillates from a top surface
to a bottom surface forming longitudinally extending ridges on both faces
of the film. The film is formed by coextruding the film through the
oscillating die plate opening causing partitioning of the resins in
different zones in the width direction of the film. Flattening of the
film results in a film with side-by-side zones formed of different
polymers or relative proportions of polymers.