Need help with subsurf pinching

[Stormrage]

I can't really describe the issue but I have screenshots,
https://imgur.com/a/GkLpcu1
Can anyone help me out figuring out the correct topology to avoid the pinching?

[Mailer]

I could be wrong here, but I believe part of your topology problem could be due to the fact that you have an N-gon as highlighted here: https://i.imgur.com/x5FidFh.png
An N-gon in this case could be a face consisting of more vertices than 4, which is generally not a very good topology for most purposes. You might want to split the face down into trigons and tetragons: faces with 3 or 4 vertices at most: i.e. triangles and squares.

[Stormrage]

Originally posted by Mailer:

I could be wrong here, but I believe part of your topology problem could be due to the fact that you have an N-gon as highlighted here: https://i.imgur.com/x5FidFh.png
An N-gon in this case could be a face consisting of more vertices than 4, which is generally not a very good topology for most purposes. You might want to split the face down into trigons and tetragons: faces with 3 or 4 vertices at most: i.e. triangles and squares.

It wasn't a N-gon originally, but it got to be one after I messed around trying to fix the issue.
Thanks for pointing it out(can't beleive I missed it), will fix asap and and see if it helps.

Edit: I fixed the N-gon but the issue got even more noticeable...

[Mr Chappy]

Hi,

Do not split this into triangles, this is very definitely not something that you should be doing with subsurface modelling!
Quads are best but the occasional n-gon or tri in the right place is acceptable, at times, when doing a hard surface model that will not deform.

When dealing with very curved surfaces such as this it is much easier to cut into the circular object if it has more geometry. You don't have a great deal which is why you are struggling.
It looks like you are using a 16 sided cylinder, try using a 64 sided cylinder(or a 128 sided), it should reduce the amount of pinching significantly and make correcting this easier.

You can then use the "LoopTools" "Flatten" tool to make sure that all the points of the n-gon are on an even plane, when they are not it will add to the pinching problem.
You can try this on your current model and you may get an improved result, it's worth a try!
If you have not enabled "LoopTools" in the “Add-ons” tab under preferences then you should, it's an essential add-on for hard surface modelling.
Using the "Flatten" tool to good effect in HS modelling can be a little bit trial and error but it is very effective at times!

Have you looked at the "Hard/Subdivision Surface Modelling" section of the guide I put together, if not take a look as there are quite a lot of tutorials and articles that should help you. You can find it from the pinned post at the top of these discussions.

[Stormrage]

Originally posted by Mr Chappy:

Hi,

Do not split this into triangles, this is very definitely not something that you should be doing with subsurface modelling!
Quads are best but the occasional n-gon or tri in the right place is acceptable, at times, when doing a hard surface model that will not deform.

When dealing with very curved surfaces such as this it is much easier to cut into the circular object if it has more geometry. You don't have a great deal which is why you are struggling.
It looks like you are using a 16 sided cylinder, try using a 64 sided cylinder(or a 128 sided), it should reduce the amount of pinching significantly and make correcting this easier.

You can then use the "LoopTools" "Flatten" tool to make sure that all the points of the n-gon are on an even plane, when they are not it will add to the pinching problem.
You can try this on your current model and you may get an improved result, it's worth a try!
If you have not enabled "LoopTools" in the “Add-ons” tab under preferences then you should, it's an essential add-on for hard surface modelling.
Using the "Flatten" tool to good effect in HS modelling can be a little bit trial and error but it is very effective at times!

Have you looked at the "Hard/Subdivision Surface Modelling" section of the guide I put together, if not take a look as there are quite a lot of tutorials and articles that should help you. You can find it from the pinned post at the top of these discussions.

To fix the N-gon I've cut it in two quads and circled a loop around the whole object so there were only quads left.

I've already added more cuts to fix various issues, the cylinder started with 6 edges. Adding more geometry is my last resort as this object is only around 3cm in size comapred to the 130cm of the whole project. I guess I'll have to do it, though 128 sounds like an overkill for such a tiny area, I think I'll up it to 32 first and see how it goes.

Thanks for the suggestions, I do already use LoopTools but I will check the guide out and see if I can learn some new tricks :)

[Mr Chappy]

No problem!

When the object is this small in relation to the greater whole there are other options, like not using subsurf...
Just use a 64 sided cylinder, create your shape, set the whole object to smooth shading, then use Bevel on the edges to get the Hard Surface look.
Any shading issues that are left can be fixed with a few extra support loops or using inset faces (i) on key regions. "Auto Smooth" under "Normals in the "Object Data" tab of the "Properties" window can also be very effective.

[Stormrage]

Originally posted by Mr Chappy:

No problem!

When the object is this small in relation to the greater whole there are other options, like not using subsurf...
Just use a 64 sided cylinder, create your shape, set the whole object to smooth shading, then use Bevel on the edges to get the Hard Surface look.
Any shading issues that are left can be fixed with a few extra support loops or using inset faces (i) on key regions. "Auto Smooth" under "Normals in the "Object Data" tab of the "Properties" window can also be very effective.

That is a great idea! Guess I've already developed a bad habbit of relying on subsurf too much, lesson learned though! THANK YOU!