Subdivision Surface loses sharpness

I learned recently how to use Edge Split and Subdivision Surface to create smoother objects. My issue is after performing a boolean, the subdivision surface distorts the bottom.

Here I have a partial ring I created, by hollowing out a cylinder, then cutting off the bottom.

Next if I apply Edge Split, then Triangulate and then Subdivision Surface, the bottom becomes deformed.

I know this is a known issue, but none of the videos I watched or articles read showed me a simple solution to solve this.

Does anyone a trick to enable creating a smooth partial ring. I could hide the bottom, like this AI image does, but if anyone knows a simple solution I would like to learn it.

Thanks

Put the boolean in last and don’t apply it. You can disable render for the cutter.

Hi.

As you mentioned, and have found out, Booleans and Subdivision Surface dont play well together.

Better to chop off yr circle or use arc, and then extrude, mark sharp edges and then add SubD.

Hope that helps.

PS, this is the second AI image I have seen of a tv set with the words ‘bubble report’ on it, am I doing yr coursework for you?

An edge must be formed to hold the bent part.

saa.blend (1.1 MB)

See the video link for more information

John Dickinson - YouTube

Apply the boolean modifier and mark the edge creases like here.

There’s nothing about this shape that requires using a boolean. So eliminating that part of your approach would solve all of the resulting problems.

That is the only way I know how to create it. How else would you do this? I used two booleans, one to hollow out a cylinder, and one to cut off the bottom.

Would you bend an object instead? Thanks

Make a circle, with enough verts.

delete verts extrude and scale in.
move 2 verts down a bit

image
extrude to give depth.

No Boolean required.

I know how to create a circle, the rest I do not understand. How do I add vertices? Is that the same as adding loops?

How do I move vertices down?

Thank you

It sounds like you need to spend some time learning some basics of modeling; it looks like the way you’re going along at present is trying to use various methods which may or may not work (ie, using the right vs wrong tool for the job), without knowing the fundamentals.

Here’s how to do it from scratch. But it sounds like you really need to learn some things about modeling first. Its a good tip thorn gave.
Good luck. Hope it helps

Thank you, I will watch when I get off work.

Sounds to me like you really need to learn the basics before you tackle something like what you’re trying to do.

Start with this:

I am not a complete beginner, and I never have a desire to build donuts. I only build scenes or props I need for IClone and Omniverse.

Thanks for your suggestion though. I have seen that tutorial years ago. I am using 4.0 Alpha, going back to 2.8 isn’t very appealing.

I never recommend the donut tutorial series because it’s much too long. rambly, and doesn’t teach you how to fix the multitudes of problems you’ll have while struggling with it. It’s kind of a rite of passage for Blender users who learned when it was the only thing around, but today there are much better options.

But that it teaches you with the help of a donut isn’t particularly relevant, nor does its Blender version matter (much; anything from 2.8 on usually works, and he has a 3.0 version out). You won’t find 4.0 (bleeding edge) beginner tutorials by the better teachers, because Blender develops too fast for the sort of investment a tutorial series is for a creator. Whether or not you want to ever make donuts doesn’t matter, but learning how to tackle various kinds of modeling challenges, that is important. Those skills transfer.

Based on what you said you don’t know, you’re still mostly a beginner, whether or not you’ve been using Blender for a while. IME it really helps to start out with a good basic tutorial series rather than winging it based solely on what you might want to do as a personal project. I usually recommend Grant Abbitt. He does mostly low poly modeling and game art, which boils a lot of modeling down to its essence. Again, the skills transfer, but you don’t waste a lot of time on stuff that doesn’t. I like him especially because he does teach the sort of thing that others often miss – how things commonly go wrong for beginners, and what to do about it.

When I’m put in charge of Youtube total content control management, I’ll be deleting that donut tutorial from the internet.

You sure? You don’t have to make doughnuts if you don’t want to, but perhaps a refresher course on the basics might be in order.

I’d be wiling to be that a solid 20% of current Blender users (including myself) are where they are because of Blender Guru.

Maybe this is a case where NURBS can come to the rescue… to make a perfect round ring and circles…

TwoNurbsCycles.blend (113.3 KB)

You could select the bottom faces for deletion a lot faster with X-ray and B/C, or shortest path, solid modeling other than that though :slight_smile: