This is something I've been looking for for a very long time and found no answers to: how do I make the mirrored side of an object a "real" object with selectable mesh?
If I apply the mirror modifier to an object how can I separate the two halves so that they become two separate objects that can be edited independently?
The Mirror Modifier has a Merge option.
Untick that! - check that the checkbox is not checked, so you have to separate objects while working with the Mirror.
After applying the Mirror modifier, you can go into Edit Mode and use L in Face select mode to Select Linked.
That means you select all faces that are connected and because you don't merged before you can select both halves of the mirror separately.
Now press P to separate selected. Leave Edit Mode.
Now you have two objects and can go one with it.
