Scratch on unfolded cylinder


I use the following formula to unfold a cylinder

The cylinder is unfolded but the rendering is not good

Do you have any idea what could be the reason ?

Best regards,

Hello @Marvin !

At a first glance, I would say that there is several elements at the same position.

Could you please share your data?


Bonjour Francois,

Thank you for your answer.

I think you are right because the problem don’t appear if I “clip” the cylinder. In this case, one part is OK but not the other one.

Clipping :

Part OK :

Part NOK :

I will prepare the data to send.

Thank you

Hi !

Here is the link to download the mesh : model

Thank you in advance.

Looks like you have unconnected elements inside your volume. It maybe the root of the issue.

If I apply extract suface filter, then clip to see inside, I can see internal surfaces (I’ve added a slice with bold lines to emphasize the issue):

Could you please share your pipeline ?


This part is the inlet part of an axial fan. Just after this part, you have the rotating part then an outlet zone with a “rectifier” (not sure regarding the translation).

The same issue appear on the 3 parts.

May be we see on your picture the differents areas from the decomposition ?

Best regards,