Thermoforming of plastic sheets over a model includes varying the thickness inthe area that is stretched over the model so that when it thins it becomesmore uniform in thickness. The plastic sheet is fabricated in a substantiallyuniform thickness but with a preformed a complex profile or 3D area thatpartially builds in part of the area that would be stretched so that it thinsmuch less than a flat sheet. Combinations of these elements may also be made.
