I am not sure how to model the oval highlight part of leather strap. Any tutorial teaching model similar thing? Thanks.
A good exercise is to trace out your section lines to describe the shape…typically your nurbs patch layout will reveal itself to you- The simply build your curves and surface with your tool of choice.
You can likely make this shape easier with subd by following the same steps to generate your patch layout. (trace your section lines then layout your subd faces by following your guide, excepts you’d trace your layout as fairly equal squares instead of a more traditional nurbs patch layout.