Scale along Z-axis only I was trying to scale this tilted cube along global z-axis:



I scaled it by twice with S+Z, the result ended up being:



I was baffled as clearly not only it scaled in z, but also in y.

Please help me comprehend this behavior. What does locking z-axis actually do? Why doesn't the result look more like:



?
As far as I know object scale can only be done along its own axis (X, Y and Z).

So if we have this cube orientation (rotated 45 degrees around Y for instance):



it cannot be scaled in the global Z axis only.

That's why we have this result:



So to obtain the wanted diamong shape, you need to either:


Apply rotation CtrlA and choose 'rotation'. Then scale along global Z:




Or:


Enter edit mode, then scale along global Z: