Fenders and doors etc are close panels, which are bolted on.
These big die castings are going against the basic characteristic of aluminum which is 6-8 percent shrinkage on solidification.
Now that is a volume shrinkage but it is still 1.5-2 percent in every direction.
Well, for a 70 inch wide car, 1.5 percent is an inch of shrinkage. Now they design the foundry tooling and die caster for directional cooling etc. to try to minimize that.
But the shrinkage on solidification of aluminum has always limited the casting sizes, and created a lot of scrap because of casting porosity and core shift.
Maybe that’s why Tesla is famous for panel alignment defects.