Is FBX converted to blender doomed to have messy mesh? The origin file is either 3dsMax or Maya. The mesh was clear and quadrangles back then. However, when it is opened in blender, it becomes triangular messy mesh as showed below. I have tried several FBX files. They are all like that. Am I doing something wrong? Thank you.
The mesh should not be triangulated on import. My guess is that the mesh was exported with triangulate.

You can try to run Tris to Quads operator in the Face menu (Alt-J) but usually it will not give the desired result.