This flash ad for netbeans 5 illustrates perfectly the principles you described to make a smooth animation:
1) the background rotates and appears to do so smoothly because it's all gradients (not hard egdes)
2) the figures that go it and out have complex shapes (so it is harder for your brain to see the imperfections) and it you look carefully you'll see that they have a blue outer stock to 'melt' better with the background.
Smoothness definetly seems to be more a trick-the-brain thing that a pure cpu thing.
Link |