Subsurf smoothing problem

Hi guys!

I justr modelled my first car rim and it just won’t get 100% ROUND. I tried smoothing faces in edit mode, subsurf of course, but it still has some bumps in it, as you can see on the pic. And now 2.6 Million polies…
I experienced that several times now, also modelling a football with hexagons and pentagons, that some sort of underlying structure is coming through. Is there any way to prevent this? Do I have to fatten something or so? :frowning:


It’s undoubtedly a topology problem, unfortunately, without seeing the wire frame you’ve built, it’s very hard to give any reasonable advice.

That said, offhand I’d guess your mesh is way too poly heavy for the object you’ve modeled. Another common affliction is interior faces or edges which distort the surface mesh and are quite resistant to smoothing, increasing subsurf levels, etc.

Post a picture of the wire frame (screenshot of a window with the model in edge select, solid draw mode.)

There you go :slight_smile: I see now there’s an error, but that doesn’t matter in this matter. I took out faces in between that made creases, so I made one screenshot with vertices and one with faces. Maybe you can make heads and tails out of this.


rim.blend (284 KB)

It looks like things got out of round when you either added or removed edge loops while there were some doubles involved.

I took a screenshot of just one of the areas with this problem.

The fix involves merging those verts, then selecting loops ona at a time and applying “to sphere” at 100 percent to make them “round” again. Before doing so, put the rim back to center as an object and get it’s centerpoint “re-centered”

I’ve attached a modded file, with those changes, It should render cleanly with even low subsurf values (2) applied.


rim_MOD.blend (253 KB)

Ah, Pappy, the man for cars!
Well, thanks a lot! That works just fine!
I guess I’ll be redoing it tomorrow and take care with those doubles… I also got a few of those when using spindup with the spokes. So spoke No 5 had an evil twin in it’s belly :stuck_out_tongue: Gotta figure a way around that problem without having to manually duplicate & rotate!

Another thing that you may want to look into.

Use mirroring and an array to remove the need for “spin dup” Then you only need to work on 1/5th (in this case) of the wheel.

Hope you don’t mind my playing around with your project, but I’ve always wanted to try this.


rim_mirror_array.blend (44.2 KB)

Just knock yourself out :slight_smile: I SURE don’t mind, cause actually YOU ARE HELPING ME! Mirroring…I’m curious now :slight_smile:
Thank you!

Pappy! How the heck did you find these loose vertices??? I keep spinning the wheel and I start feeling dizzy already! Is there sort of a trick for detecting such wrongdoers?

Btw., just to mention it as a tribute to you: I learned cutting proper holes from you “Cutting a hole into a tube without looking like a boob” tut :smiley: Or was it noob… :stuck_out_tongue: That really rocked!

Man… this array thing is weird… how did you do this? The spokes array uses the empty as offset, the Empty is rotated and thus the spokes around the empty, but my spokes now are all offset along the z.axis, coming “closer” to me and I don’t get how to put them back in place on one plane… by scaling down the empty. But how to get them placed around the midpoint… Gonna go with spindup in the meanwhile :stuck_out_tongue:
I had used the mirror anyway, but had it applied. So my only riddle that`s left is how you used the array mod and how you managed to locate the “loose” vertices. I tried to find them via the normals, but I can mainly see a spiky pile of blue!

Look at your original model with subsurf ON. Anywhere there is a spoke coming out from the rim there will HAVE to be what’s called a 5 pole. Checking for these it’s pretty easy to find a few 7 poles. The 7 poles are where the unintended edges start from.

I’ve circled a 7 pole on the right and the resulting 6 on the left on the attached image. After a while any vert that has more then 5 poles will jump out at you.

The green lines (very crude I know) are what it should look like.

As to the array, make sure that you don’t have either of the “offset” buttons checked, the only source of offset should be the empty object.

Another thing be VERY carefull with the center point of your object, look at the file I posted for more details.


I copied your array settings 1:1, I had 1 Blender oepen on my left and one on my right screen - but I didn’t copy the Empty 1:1, maybe that was the problem, maybe the midpoint got wrong.

in the meanwhile I modelled another one, which was an awful lot of work for a questionable outcome. I still make too many mistakes, stupid stuff lke rotating the whole hub horizontally without noticing before I run out of undos and so on… But I think I’m getting there.

Thanks your help! You’re doing a lot of work for me, and I want you to know this is sincerely appreciated! I hope I’ll be able to help you somehow one day. Sound engineering maybe, 2D graphics… I don’t know. Let’s say I owe you :slight_smile: (yes, and you owN me :p)

All right now, I got the thing made like Pappy - array modifier (worked just fine)+mirror at the same time. Just merging the spokes with the hub is gonna be a pain in the butt. Well, now I made a test renderimg and STILL that thing isn’t quite round although it should be perfect. The rim itself is not connected to the spokes yet.
Also, I put on some reflective material and the reflection looks TERRIBLE. I figure those are “bad shadows” - looks like a raster and in one of my books it is referred to as bad shadows - though part of the is super-smooth other parts really SUCK. Well. I’ll find out sooner or later, but the edgyness of the rim throws me off. Does it need more subdivision? Also the little bulge on the hub looks like it needs more subsurf.

So I added a jpg with the stuff that sucks and the blend file to play around with :slight_smile:

Good night guys over the ocean, have a nice afternoon!


rim3.blend (332 KB)

I think you’ve got a tendency to use too many loop cuts to add detail. The result here is the unevenness in the rim.

To fix it, edge loop select each of the loops that make the rim “round” one at a time and use the “to sphere” tool to make them actualy “round” again.

All the extra loops make it much harder for you to get a clean smooth shape, try to reduce your edges as much as possible using techniques like “diamonds” to keep detail only where needed. In the attached file I also removed evey other loop from the rim. as you can see it is nice and round wil limited subsurf applied.


rim3_mod.blend (102 KB)

Hey pappy! Thanks again for the help. Yes, you’ve already told me about the “to sphere” function, I had already forgotten :o But how can I prevent the unevenness from happening in the first place? I’m doing this after a tutorial in the car making special in the Blenderart Magazine. I’m supposed to extrude a circle with 25verts (5 spokes) and align one with the y axis. But before making any loop cuts, the thing already won’t get smooth! So is there something I’m doing wrong or is “to sphere” simply the way I’m supposed to do it? :slight_smile: I’m asking because you say “to fix this” - so that would imply I did something wrong? I guess so!I mainly use the edgeloops to create sharper creases, sometimes combined with shift-E. I have to watch your “making a gap that doesn’t look like crap” again, that was very good, too.
I gotta find out more about those “diamonds” - I found a modelling thread by toontje that seems to describe the technique. I’ll delve into it!

At least I managed to follow your way of doing this with the array modifier! That advice really rocked! And it’s very nice you put up with a n00b like me (that can’t even “listen” properly…:spin: ) :slight_smile:

There we go… busy with other stuff in between!
So everything is connected, “to-sphered” and working out nicely, at least as far as I can tell.
The only thing that still bugs me is that raster shaped shadow thing in the bottom… how does that happen?? I still don’t know much about rendering, so I must have screwed up there somewhere…
Other than that: the light sucks, I know that, the material, too, but at least the shape seems to work out now :slight_smile: Gotta make a few more…