I think they switching it from Data tab to modifier? I found a modifier " Smooth by Angle" but it doesn't really work as in video, still a lot of sharp edge when at 180 angle, not sure how it work yet.
I don't think it's a big problem , just leave it here for future question if someone can't find it at Data tab.
Hi OOshiKatsuFever ,
That can be confusing, yes. You'll need to go to Object Shade Smooth and then the Modifier will work as expected.
Thanks for the reply, last part of the video mentioned about " Mark sharp" and showing sharp edge, Auto-smooth with 180 degree angle , but the Modifier doesn't really work as intended, might due to how Modifier work ?
Anyway as Jonathan said, it only showing Normal and how reflect work ,don't worry about it !