002 - Materialism 1/2

General / 20 February 2018

Hi, In the second post I am going to try to explain the logic of creating materials. And the reason is, there are tons of people who are looking at the internet, for preset materials, or textures which almost always ends up with really terrible results. And I am going to try to explain why.

Images are property of ivabox

Before even trying to create anything, we need to understand what is "material" and how do we perceive them.

  • The photons from the light source bounce - reflect from the objects
  • That photons come to our eyes
  • Our eyes can differentiate  three different wavelengths of light, green, blue and red. 
  • Each eye contains around 6-7 million cone cells, which can combine three wavelengths that we perceived and our brain turn them into objects.

So everything starts with the light, and reflection from the object. Then it is easy to say that, we NEED light to see objects, and every single object is reflective (except vanta black, which is %99.9 non reflective - but still reflective).  The other thing we need to focus is, our perception. We need to perceive and understand what we are creating. Just doing it from memory or from the values from the net, most of the time will feel artificial. So here is some pointers:

  • Material creation should always be done by using real-world references. We need a least couple of angles and light conditions of an object to fully understand its properties. If available the best way is to observe the material itself, if not, then trying to find as much photos as possible is the way.
  • Be subtle! This is actually to the end result. Generally overdoing some stuff might help to get to the right results. Like overexposing an object to the light, overusing glossiness, bump or anything. Then when fine tuning, we will find a sweet spot for every object.
  • Nothing is perfect. Using imperfection maps, or changing glossiness maps from the diffuse map is almost always is a must.
  • Do not afraid to compose maps. Its not necessarily to be layered materials, but maybe composited diffuse maps. As nothing is perfect or that pure.

In any render engine, there are TONS! of settings to play with, but the logic of them is actually simple. And unfortunately a lot of people only try to memorize values for certain maps, which is really really wrong. In real world, nothing is same, and nothing is perfect, so in CGI it should be the same situation as well. In the next post I am going to create a nice metal, and a painted metal, so that we can understand how to approach a material creation.