I am chinese, "niu bi" is the same meaning as the man who did a great thing like achive a goal or did his/her homework quick than others etc. Originally, we said "niu cha" instead of "niu bi", because the former one is more polite.

I am Chinese, "牛逼" means a person who did something great like achieving a goal or did their homework faster than others etc.

Originally, we used "牛叉 niú chā" instead of "牛逼", because the former one is more polite.