How is this possible?!

Evil raz

This is one of the default ZBrush meshes.
I was going through it then I notice this thing. The symmerty like is perfectly aligned even when the models face is tilted.

This is exact front view. I didn't move the model at an angle.

So.... How?

Shadownami92

I believe the mesh could use zspheres or something as a rig to pose, or a blend shape. Either way it would have a non slanted default set up I think which it would reference for symmetry, if not then it could be doing something fancy with comparing vertex ids or something. But I'm pretty sure it's the first thing I mentioned.

Bal

That model is just using posable symmetry, you can see it in the Transform menu.