here is more
http://www.f-22raptor.com/st_fa22tricks.php
2.0 Continuous curves
The F/A-22 uses a combination of different ways to keep radar waves from bouncing back to their origin. The most sophisticated system is the use of so-called continuous curvature.
Many of of the surface shapes of the F/A-22 are curves with constantly changing radii. These scatter radar beams in all directions instead of back to the radar source. There are no right angles on the exterior of the design.
In order to calculate the curves and the effect they have on radar reflections form any point in 3D space, requires a tremendous computing power.
The first plane using this technology :: Equally sloped edges and continuous curvature to reduce radar echos to a minimum
extensively is the B-2 stealth bomber, also known as the flying wing.
Since computer- and software development has sky-rocketed over the past 20 years, prediction models can now be calculated quite precisely ,taking in account radar reflection versus the shape of the plane, while supporting more naturally aerodynamic shapes.
1. We never said that plan from isn’t viable we said that the aircraft uses plan-form alignment and curvature.
2. I present to you, the B-2
The aircraft uses very few if any faceted surfaces. and since the RCS is smaller than the F-117 we conclude that curvature alone when properly used, is a important aspect of modern stealth design.
# The first stealth plane was the F-117 which first flew in 1981 and remained top secret for most of the 1980s. It had surfaces like a flattened pyramid with intersecting planes like the facets of a cut diamond. It was used to attack the Iraq centralized communications, command and control centers in the first minutes of the Gulf War in 1991. No missile was ever shot at the F-117 at that time, and it sustained no damage from enemy fire. During the rest of the Gulf War, it scored over 1600 direct hits with no losses.
# The second stealth plane was the $2 billion B-2 Bomber which was approved in 1981 and first flew in 1989. The B-2 uses a newer way to achieve stealth called continuous curvature which also directed radar waves away from their source while more naturally supporting aerodynamic shapes. While the B-2 is four times larger than the F-117, its radar cross section is smaller. It can also reach anywhere on earth from the U.S. without refueling, carry heavy payload of 40,000 pounds and operate at 35,000 feet or 50 feet. The point is made that the Air Force expected to build 133 B-2 Bombers, but that was cut to 75 after the Cold War ended and to 20 in 1992.
Notice the tear shape? 
Now look at the Raptor, notice the nice clean curves? there would be more of a tear shape if it wast interrupted by the huge tails.
Look at the F-35
The B version is a little chunky but you get the picture.
So curvature is used for the top and bottom aspects, because it makes for a better aircraft than faceted surfaces. and Plan-form is uses on the wings, nose intakes tails ect.
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