HOW can I Improve my shading and look Development skills?
Juan Diego González, Chile
Before we start building up our shaders, we need to know exactly what we’re trying to recreate, so pull up a few images from Google or even your own photographic references if you have any. Pay really close attention to the way the light interacts with the surface and how the reflection is being scattered, absorbed and distributed across the subject/object. Typically in film, your reflection/specular value should always be left at 1 to achieve physically plausible and accurate results. That being said, I believe as long as the final result looks convincing enough, then you can play around with the specular intensity. Most surfaces such as wood and plastic will range between 1.4 and 1.6 IOR, which gives us a good ball park figure to start with. Once we’ve got our references of what we’re trying to create, let’s set up a HDRI for fill and a directional or area light as our sunlight.
If your shaders appear to be overexposed, first try adjusting the intensity of the HDRI and sunlight before adjusting the specular intensity, which should typically be set and left at 1. The majority of the time, shaders are let down by the lack of detail which comes from a well-made roughness, bump or displacement map. If we use the wood in this piece as an example of how to build the shader, we need to firstly connect a high resolution (1/2k) tileable wood texture into the diffuse colour parameter. Next, we take that diffuse texture and create a specular map out of it by making it black and white, followed by adding a Levels correction. Next, we need to invert the specular map to create a roughness map.
For now, we can leave the specular map out and plug in our roughness map. By using a roughness texture, we’re telling the surface to reflect light differently based on roughness at different points on the surface, creating a random look. As light hits the surface, it will now react differently at certain points. On the surface, more light will be reflected back to the camera, creating a more glossy look, and in other areas light will be spread over the surface creating a rougher look. Next, we need to add surface detail by plugging the specular map we created into the bump parameter.