How to model Spoiler with correct dimension for model audi?

what i know.. we will get approximately dimension.. first we must model the rear car.. then, model the spoiler..

is there another methode?

Have you checked forums.audiworld.com ?

You can start with anything you want for modeling a car.
I know people that create cars starting from windows.
As long as you have a reference geometry, it's easy to create the rest of the car close to reference object dimensions.

thanks for the information. Alex Moiceanu