Problem with displacement depending on TurboSmooth

[EugeneOny]

Hello everyone! Please tell me what the problem could be. I have an object like this (screenshot 1) and on some parts displacement is not displayed correctly at TurboSmooth iteration 2. If I set iteration 1 it is a little better but the problem moves to another area (screenshot 2). At iteration 3 at first glance there seems to be no problem, but on those areas displacement is displayed somehow strangely (screenshot 3). There is one more thing, if you go to the developer settings and uncheck "Apply displacement autobump" the problem is completely eliminated in any combination. I dropped the normals on the object, rebuilt it again but still nothing helps. Thanks for the answer!

[maru]

I am not aware of an issue like this. Would you be able to share the problematic object archived with all materials at https://support.chaos.com/hc/en-us/requests/new ?

[EugeneOny]

Sent, Request #377998.
Thanks for the response

[NazarVitkovskyi]

(Report ID=CMAX-1648)

[maru]

Hi, we took a closer look at this and there are definitely some issues with the scene itself:
1) The texture is not seamless or tileable. You can check that by opening it in Photoshop and offsetting it by 50%. So some seams are bound to appear no matter what mapping type you use.
2) The UVW mapping on the object is very random. You can check that by applying the Unwrap UVW modifier and looking at the editor. All faces are inverted (although I am not sure if that's a problem since ALL of them are inverted). If you improve the mapping, for example by using box mapping, the result looks better (although seams are still visible due to point 1).

This doesn't however explain why disabling autobump fixes the issue. We will look into this and share any findings with you.

[EugeneOny]

    Hi, you are absolutely right, the texture has seams that I have now eliminated so that they do not affect the picture in any way. But there is one nuance, when I assign box mapping, the displacement still remains faulty. It seems that these are common manipulations and it was difficult for me to make a mistake in repeating your recommendations (I am attaching screenshots below).

   At the moment, the only thing that eliminates the problem (your person told me about this via email) is to assign a UVW XForm to the object and tile it as in the bitmap 14 by 14, and set it to 1 by 1 in the bitmap. If I understood correctly from the explanation, the tiling of 14 is large and can cause some defects.

   Thank you for considering the issue and for the recommendations