PotaToon materials are divided into three types: General, Face, and Eye.

General: The default type, used for most parts of the character such as the body, clothing, and hair.
Face: Recommended for facial surfaces and eyeballs to ensure proper shading and detail handling.
Eye: Designed specifically for pupil-only meshes. If the eyeball and pupil are not separated into different submeshes or materials, use the Face type instead.