Theoretical SUB-D


definitely this is one of the most great thread I’ve ever seen :slight_smile:


great thread :thumbsup: learned more from it then reading endless tutorials, and only at page 10 yet , someone ( not me, im the lazy guy ) really should compile all these really helpfull stuff into a couple pages without bumps ( like this comment ), im still dazed of all that helpfull input.

considering to completly rework my current WIP now. cause a lotta mistake i couldve avoided knowing what i know now ( ).


My contribution, ipod u2 only sub-d, no aditional pieces.


Lincoln Hawk: There’s some smoothing issues around this corner. I can’t really help as I’m a newbie at sub-d but im just pointing it out. See attached image.


Lincoln(and Ian) Here is how I would model the corner you are refering to, hope this helps:



Hi all

I am making a piston and i want to make a hole for the connecting rod. I am trying to make the hole with the method of celticdog at the page 28 of the theorical sub-d thread

Yeah with a brand new sphere it’s rock but it’s make a strange oval in a cylinder. I don’t understand how place verticles to avoid this longitudinal deformation and to have a great round hole.

So I make my verticles
I collapse the vertex
I chamfer
And I drop my &%$ CPU in the stairs :twisted:

Surely that i miss something in the celticdog method but what? I tried to move verticles by hand but it’s make a kind of heavy mess when i apply meshsmooth.

Front wires, before chamfer
Wires after chamfer
render, no hole

Is there someone who can explain me that?


i am no expert at this
but as far as i can see you have no horizontal lines on your
cylinder. Those horizontal edges coming out of the hole should continue further.
no wonder you get weird results. :slight_smile:


Louis.cho did u extruded the polys inwards and deleted them? And then chamfer the edge loop?


after the chamfer i want to bevel ,01 extrude inward and bevel again. Like the trick to the page 28.
I can do it now because the oval shape, i want a perefct cercle.

I will try to do like zukezuko said and give some news(after the job!)


Excellent thread (no duh), but I saw most people posting about circles, thats fine, but what about some kind of oval or triangle shape?



JonyK, that topology is fine on a flat surface, but if you had curves in 1 or 2 directions that wouldn’t work well.


It’s actually on a sphere, a pretty high def sphere so it is curving at an angel, but probably nothing to radical.
edit: I did take a few more looks at it and it seems it does create a deformation around the object, thanks for your input.


Thanks ToddD, sorry for a long time. Help me a lot.


Cool this seems like the place to be, I’m trying to model some detail on a curved surface. So I’ve got some circular indents in it which I can model fine, see the first couple of pics. I can cut and end my edges efficiently and get a nice smooth circle. When it smooths it also keeps the curve of the surounding area and so the surface smoothly blends into this circular indent area. All is good using similar techniques to previous responses.


My problem comes when I need to add more detail, have something that doesn’t cut into the surrounding geometry quite so cleanly, like a square shaped indent as before, not a circle. So I need 4 edges for the square, but then more to get the corners and to stop it turning into a circle when smoothed, so that’s 8 edges I guess.

This means I’ll need more cuts in the corners to maintain it’s sharp edges when it is smoothed, but I can’t seem to cut these in an efficient way without messing up the surrounding topology when smoothed. Please see my different approaches in the pics. I also tried as in the first picture, but finishing the edge loops at these corners, creating tris which is bad, and also it’s not great when smoothed as pinching occurs.


I would greatly appreciate it if you could shed even the smallest light on my problem, maybe I’m just missing something really obvious, but this is the only thing in modelling that keeps tripping me up!
I’ve tried using the polysculpt in Maya and smoothing down or my bad edges, but this doesn’t help. I guess the question is how do you make cuts into an all ready regular curved surface without messing it up when it’s smoothed?

Thanks for reading this, I appreciate the time.


One thing I hate about modelling is when you have to stop and ask yourself “How do I keep this quad?”.

I can see to ways of doing this. One is to pinch the edges into the four corners, or to create extra parellel edges. As for the shading bumps you must keep your edges more spaced apart, and then manually try to keep the curved surface shape you want.

NOTE: I kept things apart so you can see the edges. So no tight corners.

The above is the best way I can think to insert a sqaure shape into a quad polygon. If you want to avoid shading problems then I think you have to create more edges then you were orginally doing.


Yeah definitely that works in terms of adding all the detail and terminating it in the corners, it keeps it all quads BUT those corners are pointy when it’s smoothed which I really don’t want or solve my problem. Also adding in those extra loops at the end have made your whole sphere have a square feel in your last picture where they are now. These are the problems I can’t defeat, please someone find the solution!!


I tried before to get this thingy on the sphere. The prob is that when you extrude the face and then apply the smooth modifier, it gets round because the faces around that face ar not sub-ded.

I started with a new sphere and converted it to a poly. I then selected a face and applied the MSmooth 3 times, which gave me smooth results so far.

Then beveled and extruded. (You can refine the edges for better form of the thingy like yours)

Then made nurms sub-d with 2 iterations.

It’s not perfect at all, sub-d seems to have probs with the tris caused by MSmooth. I probably could try to use more inserts. Any suggestions for improvment?

I don’ check this one by Jonky! Could you explain the details plz.


I had a problem which looked a bit like that, i fixed it with changing the corner
its not perfect. Only the right top corner is done :


At the moment i have a problem with Sub-D modelling i was building a round
cylinder with square parts coming out of it, i am almost done but i cant get it
finished because it smooths not good.

If ya like here is the url to the post :

I hope this thread gets its speed back, like in the beginning, its a wonderfull thread.


What software are you guys using?

I was playing around with SoftImage XSI 5, and they have a hard edge feature. Solves this problem real quick! Wish they had that in Max.