This course will look in the fundamentals of modeling in Maya with an emphasis on creating good topology. It's aimed at people that have some modeling experience in Maya but are having trouble with
displacement maps will literally add geometry to the model to achieve a high-res result. Game engines, while able to handle a lot more polys than previously, still can't handle THAT much more geometry. Normal maps achieve a simulated high-res look without adding geometry at all.
I'd like to add a little to this question. Since visually they're alike, why whould you wanna use disp. when you can use normal maps?
Since normal maps are usable in realtime rendering and disp. maps aren't, I'd assume that disp. maps are a lot render intensive than normal maps
Liter is French for 'Gimme some ****ing cola before I break vous ****ing lips!"
Yes, displacement maps are a lot more render intensive, but normal maps don't ACTUALLY alter the geometry. For instance if you look at the silhouette of your normal mapped model, there will still be edges. - normal maps still have the same basic idea of normal bump maps in how they only affect the lighting during the render process - so it still has the problem where the more parallel you view your surface the less of the normal map detailing will be seen. That's the way I see it anyway...
If you have no restrictions regarding poly usage (ie. rendering a movie) there's no reason to use normal maps, as displacement maps give an actual high-res result.
As was mentioned, because normal maps are only simulated high res detail and the detail ISN'T actually there, you still see the profile and geometric limitations that the low-res model originally is. Which isn't very condusive to high-res movie rendering.