perspective and backgrounds

[ram]

it's a four point perspective so ofcourse it's warped >.<
well four point perspective isn't covered in manga... (well maybe some put it but it's really difficult to use)
i saw some of four point perspective in scenes in anime that are looking from bottom to top.. to make it look big or something.. and there are others but don't know when and where it should be used.

well i for one won't put something i don't know how to draw.. >.< (it's not really that hard to research anyway.. I've seen pictures in google)

[Rio]

4-pt perspective may actually be used for the fish-eye look. They don't need to be used for sweeping background shots like that though that's usually the most obvious use of 4-pt perspective. You can get the fish eye look when you look out the peephole on the door.

[Hamachi]

I probably mentioned this before, but you can tell four-point perspective if there are easily distinguishable vanishing points above and below your eye level. Three-point will be either above or below, but not both.

[ram]

thanks for the answers but i think information about curve walls would be much better than talking about four point perspective.. >.< i don't plan about putting that in my manga
don't plan to put it now anyway... >.< is what i did in the first example the correct answer? i don't feel like it is

oh i just found the video of john hathway

here's a video of how he made that fish eye lens thingy..