PBR Shader Parameters

In this tutorial you will get familiar with PBRShader's parameters. You will see how change of parameter values
affect materials using PBRShader.

Agenda:

• PBRShader look - basic parameters
• PBRShader control parameters

Scene setup

Let's use custom scene composer to set up the scene.

PBRShader look - basic parameters

In this section we will walk you through changing and setting basic PBRShader parameters:

• alpha and base color
• metallic and roughness
• clearcoat parameters
• fresnel parameters
• perlin noise
  During that, we will use update default parameter methodology known from Procedure tutorial.

Alpha nad base color

Metallic and roughness

Clearcoat parameters

In SkyRenderer's PBR shader there is a clearcoat (thin outer layer) behavior modelled. It is disabled by default,
but can be enabled at any time.

Fresnel parameters

In Physically-Based Rendering (PBR) shading, Fresnel refers to the way light reflects off a surface at different
angles, particularly how more light is reflected at grazing angles. This effect is modeled using the Fresnel
equation, which describes how reflection intensity changes based on the incident angle and the material's
refractive index. In PBR, the Fresnel term is often incorporated into specular highlights and is crucial for
realistic materials, like metals and dielectrics, as it helps achieve more accurate reflections by blending
between direct reflection at normal incidence and sharper, more intense reflection at glancing angles.

Perlin noise

Perlin noise is a gradient noise that can be applied in various ways to create procedural perturbations
of textures or geometries (see Wikipedia).

SkyRenderer PBR shader has a few built-in ripples based on improved Perlin noise that can be applied to normals.
There are three types of built-in noises:

• perlin_noise_type=1 Smooth,
• perlin_noise_type=2 Marbled,
• perlin_noise_type=3 Crinkled.
  Also, you can control frequency of a noise with perlin_noise_frequency parameter.

PBRShader - control parameters

These parameters are used to control PBRShader interaction with other parts of SkyRenderer's system. Among many,
there are a few worth mentioning (often used in SkyRenderer's use cases):

• tex_scale - scale of a texture
• use_reflections - disabling that parameter will stop ray generation after first hit

Summary

In this section you have learnt:

• PBRShader has many parameters that affect shader appearance.