I'm following this tutorial: https://www.youtube.com/watch?v=jCVEtLjpeB8

And when I add the Subdivision Surface modifier there's a hole at the bottom of my cup. I have no idea why this happens and how to fix it.

bottom of cup has hole in it

  • $\begingroup$ Maybe one of your verts isn't in the centre? $\endgroup$ Dec 2, 2022 at 2:30
  • $\begingroup$ Can you share the file? Or at least show a screenshot that allows us to see the topology (Edit mode or something). $\endgroup$ Dec 2, 2022 at 6:40
  • $\begingroup$ Anyway, it looks more like an black object overlapping than a hole to me. A hole wouldn't be that dark. But I'm still guessing here. $\endgroup$ Dec 2, 2022 at 6:41
  • $\begingroup$ @mqbakamqbaka I don't know how to post another image into a comment but it looks black on the solid mode, and when I toggle x-ray it just shows the same hole but kinda see-through? It's definitely not an object $\endgroup$
    – Rosie
    Dec 2, 2022 at 7:24
  • $\begingroup$ You can edit you post and post a picture or share the blend file here -> blend-exchange.com and add the link to your post. $\endgroup$ Dec 2, 2022 at 7:27

1 Answer 1


The problem is that you haven't enabled the Merge option in the Screw modifier. Therefore you have many overlapping vertices in the center area. This creates a bad shading since you have set the object to Shade Smooth but didn't enable the Normals > Auto Smooth option in the Object Data Properties.

Auto Smooth will get rid of the visual effect, but you still have a lot of overlapping vertices, so you should definitely enable the Merge option, otherwise your mesh will stay unconnected in the center. By the way, the inner vertex of the glass bottom is not exactly in the center, so there is a hole. I would select it and set the Y value to 0.

merge vertices

The slightly off vertex:

off vertex

  • $\begingroup$ Is it Blender version related, then? I couldn't seem to have any black dot. $\endgroup$ Dec 2, 2022 at 10:17
  • $\begingroup$ @mqbakamqbaka I don't know, might be... which version are you using? The tutorial is for 3.2, I don't know if Rosie's using the same, I am on 3.3.1 $\endgroup$ Dec 2, 2022 at 10:23
  • $\begingroup$ I tried on 3.2 and 2.93. $\endgroup$ Dec 2, 2022 at 10:28
  • $\begingroup$ Maybe it's a 3.3 thing? $\endgroup$ Dec 2, 2022 at 10:30
  • 1
    $\begingroup$ @mqbakamqbaka Might be.. but the good thing is, this way it was possible to detect some flaws in the object ;) $\endgroup$ Dec 2, 2022 at 10:37

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