You should always respect your parents and avoid making them feel insulted. No doubt, every man is free to decide where to study and where to work, but never cause insult or pain to your parents. Either you convince your father in a very polite way and get his real satisfaction, or obey his order. It might be difficult sometimes, especially when you think that your benefit is away from the choice of your parents, but be sure that Allah (SW) will grant you more success if you obey your parents.

Remember the promise to the Pious : (And whosoever fears Allah, Allah will get him a way from every difficulty and will grant him from unexpected source) Sura 65, Verse 2 and 3.  

ومن يتق الله يجعل له مخرجا ويرزقه من حيث لا يحتسب ومن يتوكل على الله فهو حسبه

Wassalam.