Keep subsurf circle round when adding loop cuts

I’m modeling a simple wrist watch. I’ve got the basic shape, but the face is no longer perfectly round where I’ve added loop cuts to model the watch band posts. No matter how I move the verts in those “flattened” sections of the circle, it remains distorted, I’m guessing because as you add edges, subsurfaced areas become more creased. Any ideas? Thanks.



You could use the “to sphere” function, ‘Alt’ + ‘Shift’ + ‘S’

Unfortunately “to sphere” is pretty crap since 2.5, it was a lot better before. It works for some purposes though.
The “Looptools”-addon’s Circle function is handy as well.

it looks to me that all your edges are screwed
look at first pic on the edge of the watch and you can see it

if you redo it don’t deform it let it circle like then add to it !

and it should be like a circle !

salutations

Actually adding loops to a circle does make it lose its shape if you don’t smooth it out.

The way I’m currently doing this is to duplicate the evenly-spaced circle then manually adjust the verts of the uneven one to mimic it. It is not great, but I do not expect to beat the solution, since adding a new loop fundamentally alters the Subsurf algorithm’s input.

In your case, though, I think you can avoid allowing those edges to enter the circle, altogether. Add a shape like a trapezoid with the wide edge pointing toward the watch face. This is sometimes called a U-turn Quad because of what it does to loop cuts. This will die four incoming edges into two. I can sketch it out if you don’t get what I mean.

-rking

well i’m not seeing some unsmooth circles here

i see that some part of the watch are modified manually and that’s screws up eveything when yu add new loop inside!

show us a closed shot of the wireframe so we can better the deformation!

salutations

I didn’t modify the watch manually. You can replicate this fairly easily. Create a circle with 16 verts., filled. Extrude it a bit, make it smooth, add subsurf., set to 3 or 4. Add a couple of loops cuts, slide to .90 to get a coin like shape. Now, add a pair of loop cuts that divide a “pie peice”. Toggle out of edit mode and view the flat spot. Because your increased the vert density in that area the subsurf. draws a larger radius or a flat spot.




I think your right about this. I thought about terminating that area before it entered the inner circle, but this was for the weekend challenge and I was running out of time. I guess I’d have to rethink the whole approach if I wanted a perfectly round face.

Thanks,
AN

The thing is, the more I tried to smooth it the worse it got. Moving the verts “outward” just moved the flat spot out. Adding a third loop cut in between the two problem ones and moving (rounding/smoothing) things out created a rippled edge. I could reduce the effect by moving some verts but I was afraid the whole mesh would start to misbehave if I later needed to scale or change things.

Few tips:

  1. Try and avoid using unevenly distributed vertices to describe circle.

  2. If you want a string of edges to be “automatically smoothed” when subdivided, modify the topology to make it into an edge loop. In your particular case, add an extra loop cut.

  3. (IMHO) Plan your topology before you start, and un-check “Apply modifier to editing cage” of your sub-d modifier during constructing phase.


test.blend (449 KB)

(I tried to mimic what I saw from your image, sorry if there’re any errors.)

had some problem reproducing your problem!

cause i think now bmesh has been merge and i get ngon instead of tri’s and quad !

so it’s new way of doing things !

but yes need to plan what you do and try not to manually verts randomely !

always follow lines

and dont’ add tri’s like circle center at the beginning wait at the end
then it will help better see waht you do when adding loops and have more control over it!

happy 2.6

Hi there, I followed a tut that showed you how to make a watch and you’re issue didn’t come up. Try having a look at how he did it. Not sure if you can post links here so just google creating-a-fancy-watch-in-blender.

Nice! Makes sense, thanks.

Thanks everybody for the info. I think I’ve got more than a few ideas of how better to handle this in the future.

AN