"""""""""There are no even such a term Like 3D modelling when Marcello Gandini created Countach or Miura."""""""""""

No, he would have used things like "French Curves" And "Drafting Machines" and a heavy "understanding of math" for the ability to actually use a French curve...... Also understanding that he was creating a 3 dimensional object which needed to maintain the beautiful characteristics of Curvature...

He most definitely didn't just draw something and say "Look at that!"...............