Opacity/Subsurface Masking

Part 1:

In the following sections we will set up the Opacity output for the material, this part of the graph affect the material in two ways.

1.) It controls teh amount of subsurface scattering that occurs on the surfae of the mesh

2.) With translucency enabled,it controls how opaque/Translucent the material is.

So, this will affect how the Opacity output is used depending on whether we enable translucency or not

(Note: The translucent version of the material is quite expensive, use carefully, ideally any objects that use this shader should mip out to a cheaper version of the material quickly)

It is important to note that Opacity serves two purposes in this material, since our material uses a subsurface shading model, the opacity controls how much subsurface scattering happens on the surface of the object, in the opacity map, white areas = more scattering black areas= less scattering.

With translucency on the other hand, white areas = opaque, black areas = completely transparent. We need to keep this in mind as we build the opacity graph, so that we adress both these needs correctly

This first section just makes a basic mask using the texture we created earlier, but we also add some fresnel, so that the edges of the object do not become completely transparent as this can make the object feel floaty, and not very grounded in the world.