as i said before i didn't mean any offence by my comments i was just going by what i read and saw in the renders thats all so i am sorry

all cars have certain lines, the shoulder line usually is coming from the top of the fender and follows underneath the side windows of the car to give it width and definiation to the upper and lower of the car.the bmw 6 series is a good example of this especially near the rear fender where it curves downward creating the high boot, a waist line is usually a lot more subtle it can be used to change the reflection of light and create shadows and highlights it will also help to break up a side profile so it doesn't become to slap sided.
this is what i have been taught so this is what i know don't take it as the real thing.