If you were actually looking for information regarding a specific or character model from NekoPoi , please let me know, as that would fall under a very different category of content.
Researchers often use 3D Convolutional Neural Networks (CNNs), like the U-Net architecture, to "paint over" or remove these ring-shaped defects in 3D scans. [3D] Tamaki (Ring) – NekoPoi
Which of these interpretations were you looking for, or were you referring to something else entirely? If you were actually looking for information regarding