Hi, Jonathan .. Hope you're doing very well!
I am actually try to repeat that technique of cup many times to master the subdivision modifier and know more & more about editing tools.
I was wondering about something when i use subdivision surface on my new mug of tea, i kinda feel confused about (When only displaying my modifier on the mug, kinda tell me that there were triangles or even face with only three vertices) kinda like it's not sharpened at all or just like too meshy and not sharpened like i do to the mug handle and i make sure already many times:
1- Adjusting the cage to the modifier result
2- turn off displaying modifier on the mug
i find and checked that my mug full created of quads just four sides of every face ... so why it's telling me about there are some faces with 3, 5 or more vertices when i display my subdivision-surface modifier ON ...
Here are the photos:
First one,turned off display subdivision-surface modifier
second one (My issue), turn on subdivision-surface modifier
third one, turn on modifier & adjusting the edit cage to modifier result
Hey Boula, the good news is that nothing is wrong with your mesh! In the second image, Blender is just trying to show you both the unsubdivided mesh for editing and the subdivided mesh for previewing. You can see an exaggerated version of that here:
The strange shapes you get are just where the solid subdivided preview pokes outside of the somewhat transparent unsubdivided mesh. Hope that clears it up!