Table of Contents
What is subsurface scattering?
Subsurface scattering is when refracted light penetrates the surface of an object then
reemerges from it. If you want to see it happen in real life you can use it easily. Place your hand in front of strong light, like your phone’s flashlight. Well, this is it light just ntered your fingers, scattered around and came out, giving your hand a red glow. You’ll notice as the light goes through your fingers it will be stronger at the edges and weaker near the center. That’s because the more it has to move around the material, the more it will be absorbed. A material like rock will have high absorption, giving light little to no chance to scatter around and come back, and on the other side of the scale is glass, which doesn’t absorb light at all.
Why is it important?
Subsurface scattering is not a rare phenomenon, it is something that we are really used to seeing in our everyday life, so if it’s missing we can immediately tell somethings off, that something looks fake/plastic/rubbery. It is not needed for every material as I said above, high absorption materials don’t have it, but for anything, else it is absolutely essential if you are aiming for more realistic materials. But even if you don’t I think it just looks absolutely beautiful when done right.
How to achieve it?
There are multiple ways to achieve to do it with octane, let’s start with the fast way first. This uses transmission and Medium. First, create a diffuse material. Select the base color. Now enable transmission and select the color the light scattering has. Now for the third and last step click on medium and then on scattering medium. Here you can adjust how absorbant your material is, how much light it lets through. Although this method is the fastest and produces a pretty good result it is not as precise and good looking as the next method.
For this second type of material first, you’ll need to create an Octane mix material. Now go inside the node editor and create two new materials.One glossy, the other specular. Add glossy as material one and the specular as material two inside the mix material. Also, add a float texture for the amount. Now on the specular material select medium and click on scattering medium. For the scattering medium add a RGB Spectrum for absorption and one for the scattering. With these, you can control the color of the scattering. The scattering medium offers the option to adjust the density of the material, the less dense, the more light it lets through. You can add
a little roughness to both the specular and glossy material. You can also adjust the transparency of the material with the float texture we placed on the mix materials Amount.