How do you use PBR to achieve different lighting and shading effects?

1 What is PBR and why use it?

PBR is based on the principle of energy conservation, which means that light cannot be created or destroyed, only reflected, absorbed, or transmitted by materials. PBR uses mathematical models and algorithms to calculate how light behaves on different types of materials, such as metals, dielectrics, or subsurface scattering. PBR can help you create more realistic and consistent 3D graphics, regardless of the lighting conditions or the viewing angle. PBR can also save you time and effort, as you don't need to tweak your materials manually for each scene or light source.

2 How to set up PBR materials?

To use PBR, you need to set up your materials with the appropriate parameters and textures. The most common parameters are albedo, normal, roughness, metallic, and ambient occlusion. Albedo is the base color of the material, without any lighting or shading. Normal is a map that defines the direction and intensity of the surface details, such as bumps, scratches, or wrinkles. Roughness is a map that controls how smooth or rough the material is, and how much it reflects or diffuses light. Metallic is a map that determines whether the material is metal or not, and how much it reflects light directly or indirectly. Ambient occlusion is a map that adds shadows and depth to the material, by simulating how light is occluded by nearby objects or crevices.

3 How to use PBR for metallic effects?

One of the advantages of PBR is that it can create realistic metallic effects, such as chrome, gold, or copper. To achieve these effects, you need to adjust the albedo, metallic, and roughness parameters of your material. For metals, the albedo should be close to black or gray, as metals do not have any color of their own. The metallic parameter should be set to 1, as metals are fully reflective. The roughness parameter should vary depending on the smoothness or roughness of the metal surface. For example, a polished chrome would have a low roughness value, while a rusty iron would have a high roughness value.

4 How to use PBR for smooth and rough effects?

Another benefit of PBR is that it can create realistic smooth and rough effects, such as plastic, wood, or stone. To achieve these effects, you need to adjust the albedo, metallic, and roughness parameters of your material. For non-metals, the albedo should match the color of the material, as non-metals have their own color. The metallic parameter should be set to 0, as non-metals are not reflective. The roughness parameter should vary depending on the smoothness or roughness of the material surface. For example, a glossy plastic would have a low roughness value, while a rough stone would have a high roughness value.

5 How to use PBR for translucent effects?

A third advantage of PBR is that it can create realistic translucent effects, such as skin, wax, or marble. To achieve these effects, you need to use a special parameter called subsurface scattering, or SSS. SSS is a phenomenon that occurs when light penetrates a thin or translucent material, and scatters inside it, creating a soft glow or a color shift. SSS can add realism and depth to your materials, by simulating how light bounces inside them. To use SSS, you need to enable it in your material settings, and adjust the color, intensity, and radius of the scattering effect. For example, a human skin would have a reddish color, a moderate intensity, and a small radius, while a marble would have a whitish color, a high intensity, and a large radius.

6 How to optimize PBR for performance?

PBR can create amazing 3D graphics, but it can also be demanding on your hardware and software resources. To optimize PBR for performance, you need to consider some factors, such as the resolution, compression, and number of textures, the complexity and number of materials, and the quality and number of lights. To reduce the load on your GPU and CPU, you can try to lower the resolution or compress the textures, simplify or reuse the materials, and adjust the quality or quantity of lights. However, you should also balance these factors with the visual quality and realism of your 3D graphics, and find the optimal settings for your project.

7 Here’s what else to consider

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