Hello!
After watching the lecture, I was really confused as to why applying the rotation caused the scaling on the Y axis to behave differently. After thinking about it for some time, I figured it out! So if you’re confused about it like I was, here’s what’s happening:
The object scales relative to the world. Before the cube has been rotated, two of its opposing faces will be facing the Y axis. Naturally, it’ll only scale in that direction.
But if it is rotated 45º first and then scaled, the face that was previously facing the Y axis will now be facing exactly inbetween the X and the Y axis, which means that face will try to scale towards the Y axis meaning the X axis will inevitably scale as well.
If after being rotated 45º the rotation is applied, then what’s going to be facing the Y axis is the corner’s edge of the cube, which is what’s going to be expanded (forming the diamond shape) because that’s what replaced the face of the cube as the new “default facing Y axis” side of the cube, if that makes sense.
Hopefully this will help!
Thanks for the great lecture!