How to remove small creases/wrinkle on a surface?

Sometime after the filleting process, some small crease/wrinkle will show on the surface, as the uploaded surface shows. How to remove it?

Have you tried increasing render mesh quality?

Hi Mahdiyar,
Thanks for the suggestion. I tested it but the result is the same. Is it possible due to the unsmooth boundary? I uploaded the IGES file for you to check it more detail.

surface (2.2 MB)

Best Regards,

As Mahdiyar mentioned, you’re seeing the render mesh, mesh density needs to be increased for this complex shape.

Hello - is there some reason not to post a Rhino file? In any case the surface is not at all fair, there and needs to be re-made using better tools or better input curves, I would say. It looks like it was a degree 2 surface at some point in its life.


Hi Pascal,
Here is the file for Rhino format.
Suface (3.2 MB)

How was the surface created? Did you interpolate through a set of points?

Why are the surfaces degree 6?

When used for interpolation higher degree curves and surfaces tend to have more oscillations than lower degree curves and surfaces.

Hi David,

Thanks for the reply. Actually, we created this surface in another CAD software(powershape). The last step for creating the surface is chamfering with another surface. I think this would be the reason for its degree of 6. We are searching for a proper step to eliminate the crease/wrinkle on the surface, as a standard procedure.

Best regards,

Can you upload a .3dm file with the surface as received in Rhino from the other CAD software?

surface (2.2 MB)
I don’t if this is what you need. The whole processes for creating the surface were in powershape. We just output it with IGES, then import it with Rhino.

I’m confused. The geometry as output by Powershape has wiggles/creases. Why are you asking on the Rhino forum how to remove the creases. Why not work to keep the wiggles/creases from being created in Powershape? The Rhino forum is not the place to ask about Powershape.

Hi David,

Thanks for the response. Let me clarify what we want to do: As you mentioned, we were doing the processes in Powershape. Actually, we are using Powershape’s API to do some automation. We already know how to fix the crease/winkle in Powershape “manually”. But what we want to do is “Automation”.(Not each manual process is easy/possible to become automated) So, we want to know more about the fixing/rebuilding techniques for surfaces, which would be helpful for us. Since Rhino is a very powerful tool for surface construction, we asked this issue here.

Best regards,


Well…there are things you can do that are going to technically smooth it out, but they’re also going to arbitrarily change the shape. It’s not what anyone who actually cares about surface quality to any great extent does. Surface fairing is an art not a science, it’s not automatable. If you want to automate making smoother surfaces you need to do start with how the surface is made in the first place…how do these even start out?

The original poster explained that the geometry was created in PowerShape and imported into Rhino with the creases/wiggles already existing:

They also said they know how to fix the problem in PowerShape:

Perhaps the original poster is hoping Rhino has a magic tool to smooth while keeping design intent.

you made a degree 6 surface with boarders which are made of degree 1 polylines which does not make any sense. your input curves should be rebuilt to continuous and higher degree before you attempt to create further surfaces.