Circularize moving random vertices on a certain mesh

[t_aliesinriver]

On a certain object, when I use the circularize tool on any set of faces it doesn't work, and instead moves a random selection of other vertices across the mesh. When I try this on any other object, it works fine. It seems that other tools occasionally have the same issue. Has anyone run into this problem before, and do you know what could have caused it or why it happens?

Screenshots from before and after circularizing below:

[t_aliesinriver]

Adding that combining the mesh with another, non-cursed mesh seemed to fix the issue, but I still would like to know why it happened in the first place so I can avoid running into the same problem in future.

[Ιάσονας]

if i understand what you are asking and maybe this will help to create a circularize you need 4 faces, 

[t_aliesinriver]

Thanks! Maybe I misunderstand you but I don't think that's true... I regularly use two faces and it works just fine. It just creates a hexagon instead of an octagon.

It also worked fine with the selection shown after I had combined it with another object as described in my other comment.

[Ιάσονας]

i misunderstood as well i thought you were trying to creating a circle, in order to create a hole , you would need four faces,

[t_aliesinriver]

Ok this is getting kind of off topic, but I'm still not sure what you mean! In my experience, you can create a circular hole with a hexagon just as easily as with an octagon.

You do of course need to smooth it afterwards, but that's the same whichever shape you start with.

[Ιάσονας]

the way you are doing it is causing bad geometry with ngons

[t_aliesinriver]

There are no ngons though... the mesh is entirely quads, both before and after subdividing.

[Ιάσονας]

thought this was an ngon but i see whats happening now the geometry is being twisted around because of the circularize

[t_aliesinriver]

Oooh yes I see what you mean, yeah I just made that model as a demonstration so I didn't bother trying to smooth out the surrounding geometry

[Ιάσονας]

this is how i was taught

[t_aliesinriver]

I feel like both methods are just fine, it just depends on the original topology you're working with, and how much detail you need for that specific part. I use both methods regularly, as well as much larger selections of quads.

I don't think it's really possible to create n-gons with the circularize tool if they weren't there already, since all it's doing is moving vertices around, which doesn't effect the underlying topology!