Why do materials look stretched on curved 3D surfaces?

[indiancad]

I’ve noticed that applying a material to a 3D model does not always produce the expected result. On curved parts, textures can appear stretched, misaligned, or out of proportion even when the

 

geometry itself looks correct.

 

The material mapping method can make a noticeable difference, especially on cylindrical components and irregular curved faces.

 

How do you normally handle material mapping on complex 3D surfaces? Do you adjust the mapping for each face or use a different approach to keep the texture consistent?