PBR is an abbreviation of Physically Based Rendering is a method to simulate how light interacts with the model to mimic the real-life material. It is particularly a method of shading and rendering. However, it is changed from the classic shader and dynamic lights in Sumerian that use the older light algorithm.
PBR lighting and shading techniques render the metal and non-metal objects near to their real-world analogs.
It does a pretty good job of mimicking material. Additionally, it suggests a standard method of texturing 3D models thus despite what program you use to render it will act according to lighting.
PBR is immensely used in 3D software and gaming engine include unity and Unreal Engine, It is a workflow that is broadly endured in the CG industry.
Why Should You Use PBR
Before PBR many render engine had their own workflow to simulate the identical effect. If you want to switch from blender to unity there were more steps required using shaders. Which causes an increase in workload. Back then it was a major drawback.
After the introduction of physically based rendering, all the difficult steps get reduced.
PBR is an industry standard to a certain extent, so it is best to learn how to work with it. Its texture gave a really good experience.
How do we see things around us?
The terms diffusion and reflection define the phenomenon to see objects around us. Diffusion and reflection are also called diffuse and specular light respectively.
when light strikes the surface of the object and bounces off to the opposite direction relative to the surface causing a reflection. On a plane surface, this appears in a mirror-like manner. This effect is often referred to as specular which is acquired from a Latin word for mirror.
Not every single ray of light is reflected from the surface, few will be absorbed by the material and few will be scattered internally. some of the scattered light bounces off the surface and becomes visible to the eyes and cameras.
The scattering and absorption of diffuse light are changed for every wavelength of light, which is responsible to give objects their color. For instance, if an object absorbs utmost light but scatters the green, it will appear green.
Diffusion has two more complicated phenomena, which are based on the shape and the thickness of the Object include transparency and translucency. They both are different from the normal diffusion process. Thereby, to simulate these processes unique shaders are required.
If the object is thin enough then the light is often scattered from its backside then it is termed translucent. If the diffusion is too low then no scattering is observed and the complete images pass through an object intact, so it is termed translucent.
As you have already studied the law of conservation of mass in your secondary classes that “Energy can neither be created nor be destroyed, it can convert from one form to another”.
Similarly. the scattering intensity of diffuse and reflection cannot exceed the intensity of light that fell on the surface originally.
It means that highly reflective objects have less or no diffuse light and vice versa.
Energy conservation allows working with reflectivity and albedo values for the material without disrupting the law of physics. Therefore, It is considered a significant feature of PBR.
The fresnel effect describes as different reflectivity occurs at a different angle. Or it can also be said that reflectivity depends upon the angle of incidence of light on the surface. So, if the angle of incidence of light is smaller then the reflection will be stronger.
If the object is rendered with the appropriate fresnel effect, so it will show brighter reflection near the edges.
Reflection and diffusion both depend on the surface. Most of the surfaces have flaws like tiny pores, scratches, and cracks often too small to see with the naked eye. Despite being invisible to the eye, These microscopic features can affect the reflection and diffusion of light.
The microscopic features make the surface rough and the reflection of light becomes blurry. So, if the surface is smooth then the reflection will appear clear.
Presently, texturing is quite easier. The principle of the Fresnel effect and energy conservation works without any
hindrance. The artist usually required 4 textures,
Diffuse : It contains all the color information of the surface in simple words this is just a Texture.
Roughness : It illustrates that how much light is absorbed by the surface. If the total light is get absorbed then the surface is rough. And if no light is absorbed then the surface is smooth.
Normals : create the illusion of depth and texture on the surface of a 3D model using computer graphics.
Displacement : These are the king , Displacement maps add extra details to the low mesh model , and it impact on 3d model's geometry.
The physically-based rendering method causes the separation of material and lighting which makes it quite easier to design lifelike assets that seem perfect in all lighting conditions.
For How to use PBR Textures you can watch Our youtube Channel.