i never touch Opacity before, so i need to learn some basics of it.
let say i want to make opaque creature, but transparency material disable some PBR part of texture.
i am confused, how to make realistic transparency creature without PBR ?
When we talk about PBR we are talking about how the light behaves when it hits a surface. So with that said, each type of material has properties which make them different when dealing with light incidence, so saying a material is PBR is correctly saying it behaves physically right when light hits its surface.
So basically this is why in the material settings you have choices for:
Material Domain: Surface, Decal, Volume, etc (groups by material attributes)
Blend Mode: Opaque, Masked, Translucent, etc (defines how material color blends with background colors)
Shading Model: Lit, Unlit, Subsurface, Eye, Hair, etc (defines how the inputs are combined to generate the material output)
Thinking on this, it is weird think of glass or water as a opaque material, because these elements have a way to modify the light trajectory not found in a opaque element like wood or steel… Just as a guide I have made a video long time ago for someone, explaining how to basically create glass, which is transparent, it is not a definitive guide on how to do it, but it is enough to understand opacity. Take a look: UE4 - Glass Material hints - YouTube