# Creating wavy pipe lip

I need to create a wavy pipe lip just as this image shows. I'm not referring to the corrugated side, just the top lip. And the lip surface must be smooth. Is there a tool in Blender that would allow me to do this?

• This looks like a simple matter of booleans. Commented Jan 31, 2022 at 19:57
• I can boolean cut ovals but that won't get me a continuously smooth surface all around Commented Jan 31, 2022 at 20:05
• give it a few moments and @Chris will bring his geometry nodes ;) Commented Jan 31, 2022 at 20:06
• I try ;) ....... Commented Jan 31, 2022 at 20:16

Classic way ...

• Add Cylinder 8 sides (octagon)

• in Edit mode select two opposite vertices and move upward 0.2 and in two in cross direction downward -0.2

• add Subsurf and Solidify modifier

Same can be done with Surface object > NURBS Cylinder

• I was about to try making 2 sine waves and putting the sample into the screw modifier. Your solution seems much better. Commented Jan 31, 2022 at 21:42

UPDATE

Ok, here in smooth, fully procedural and non destructive:

result:

You can get this:

by this node group:

but better use this:

to get this:

changing the sin input value you can adjust:

• That's definitely impressive functionality and I'm going to end up using that in the future. But the lip must be smooth and not segmented. Is this possible with the solution you've provided? Commented Jan 31, 2022 at 20:41
• thank you very much! I updated my answer. It is now smooth and it is non destructive - you can change it without effort. Commented Jan 31, 2022 at 23:13
• I never used geometry nodes before. I don't get the meaning of the multiply nodes on the left. Wouldn't "Multiply 0.02" and "Multiply 3.2" combine to a single "Multiply 0.064"? Commented Feb 2, 2022 at 6:08
• Of course. But if you ever tried to slide a low value with the mouse, you would recognize that it is very difficult to change it because although you hold shift it still changes too fast. That’s why I added a second multiply node. Commented Feb 2, 2022 at 7:32

## Blender 3.0.

I would say those geonoodles are kosher, but I'm not sure it'd be politically correct so I won't say so.

Note:

• Curve samples should be a multiple of humps
• Catmull-Clark Subdivision smooths the shape and lowers the tips (Hump height is not accurate)
• Hehe.. this is almost identical to the answer I didn't post :D Commented Feb 1, 2022 at 18:18
• @RobinBetts I actually colored my frames inspired by your setups. Commented Feb 1, 2022 at 18:23