On some MoI 3d tutorials, I`ve seen that during line drawing it`s possible to have a live mirror. You change one side and the second side is immediately changed.

How to do that?

The second question is about blocks aka instances. Is it possible to use something like that in MoI? I mean for example when you have 50 similar objects and you have to change them. That blocks would change instantly after changing the source. Is that possible in MoI3d v4?