the goal is to understand how leather material will be perceived on a seat tufted surface with a diamond pattern.

the input is a subdivision surface

we could make a try with displacement mapping of a black and white picture. but it will be difficult to make variations and fine tune of the pattern and tuft. Also, the 3dxml is shared at the bottom of the post, for details - you need a licence with CATIA Visual Scripting app to open the model though.

the overall logic is

• input the subdiv surface
• clean it by removing star points (points with 5 converging edges)
  • they will trouble the fold/unfold
  • I remved only 1 start point in this model
• unfold the surface
• make the diamond pattern flat
• fold back the pattern to original surface
  • smooth the curves if necessary
• mesh the diamonds
• apply normal force on the diamond with softbody function
• remesh to make is lighter
  • make sure to use "preserve" option on the mesh boundaries -> mesh will stick on them
• create the surfaces (for rendering)
  • I still have a tiny hole on the boundary vertices. but not important for rendering

here are some renderings

I added small diamond holes in the leather. Being parametric, I can activate them when they are located within a heart-shaped surface.

Takeaway

I am satisfied with the result. full controlable even though not in this post (it could be in future).

it was not easy

• Subdivision must be healed -> better to use Bezier/NURBS. However, tools are there to heal it.
• need computer over 30GB when surfaces are required.
  • within mesh, no problem -> light and fast
  • when rendering quality is needed, then surfaces must be generated -> the more RAM and CPU, the better.
    • remember that the tuft effect  is coming from Softbody function, so surfaces could be a little bumpy to stick on reality.
• I am not sure how much should be shared here. let me know if you are interested by a more detailed explanation -> I am think to show softbody on 1 diamond only for example.
• I may edit the post adding parametric variation (like difference force with heart and outside heart)

big thanks to @ES for kind support to discuss modeling strategies and @VH for the industrial use case and specs.