# Ripples in SubD

I’ve decided I want to use SubD for a project I’m working on. I have no experience with SubD or polygon modeling or anything of the like.

I watched and modeled along with some demo videos by the amazing Rhino Guru better known as Kyle Houchens. This felt like a great primer.

Now I’m 1 hour into my own project and… Getting some new problems. One of them is this: I get ripples in my SubD. I have two beveled edges which I want to fade out on the end. (See pictures below and file attached). What’s a way to avoid this?

Thanks in advance for any help!

sub-d forum.3dm (4.3 MB)

I’d suggest against using n-gons in your SubD , specially if you’re new to this.
Rule of thumb is - quad topology is the ideal that you’re aiming for and quad+tri topology is where you end up.
Whenever your edge-flow abruptly ends hitting an ngon - you’ll get crappy behavior.
I’d suggest playing this on the second screen while you do your own modeling: SubD livestream Part 1: Learning to 3D model with Rhino 7 SubD Tools - YouTube

sub-d forum.3dm (4.4 MB)

Your video was actually next on my to-watch list! I’ve watched the first two parts by now It’s helped me a lot to see how you approach the problem. Very interesting to see how you’re struggling so much with the software, but still getting such an awesome result. Just goes to show that the real meta-skill is modeling, and not simply knowing some software package.

Just 1 quick question to confirm: That face on my original picture (below all the thin faces) is considered an n-gon, even though it has, strictly speaking, only 4 edges? The top edge is seen as 5 collinear edges, not 1? So what I’m showing below is not a good idea either, in general? (made a box and subdivided only the top plane to add the detail)

Yea, those video series was me just getting into the world of SubD modeling - these days I tend to struggle a bit less (emphasis on A BIT).
And in terms of your question - if something looks like a quad - doesn’t mean it’s a quad. Once you turn on the smooth display all N-gons tend to show themselves - in your case a quad becomes a pentagon.
Basically - when you have a straight edge and another edge “hits” it, it’s going to divide up into two separate edges that are co-linear (example: In Nurbs world a letter T can be made out of 2 or 3 sticks. In SubD world - it’s always going to be 3 sticks, unless something even worse is going on)

as it seems to me in this case its just one tiny little point too much…

Ahhh yes, That made it even worse!
I fixed it, but there are still ripples of course. Plus, I noticed that this kind of setup makes everything harder to manage (pulling the wrong points may create real n-gons), so I’ll be sure to avoid it in the future!