Not exactly an issue with the shader itself, but transmission is just the model having light pass through it when a light source is behind a model, which is similar to subsurface but not exact. Thickness is actually the map controlling subsurface effects, which is just light bouncing around inside the model regardless of direction
Not exactly an issue with the shader itself, but transmission is just the model having light pass through it when a light source is behind a model, which is similar to subsurface but not exact. Thickness is actually the map controlling subsurface effects, which is just light bouncing around inside the model regardless of direction