Material Properties Explained: A Beginner's Guide to PBR Workflows

Physically Based Rendering (PBR) has revolutionized 3D graphics by providing a standardized approach to creating realistic materials. In Blender, the Principled BSDF shader encapsulates this approach, offering a comprehensive set of parameters that simulate how materials interact with light in the real world. This guide breaks down these material properties in simple terms, helping you understand what each parameter does and how to use it effectively.

What is PBR?

Physically Based Rendering is a method of shading and rendering that provides a more accurate representation of how light interacts with surfaces. Unlike older approaches that used arbitrary values, PBR is based on actual physical properties of materials, making it easier to create consistently realistic results across different lighting conditions.

The key benefits of PBR include:

• Consistency: Materials look correct under any lighting scenario

• Reusability: Well-made PBR materials work in multiple projects

• Predictability: Artists can work with familiar real-world properties

• Efficiency: The standardized approach makes material creation more intuitive

Understanding the Principled BSDF

Blender's Principled BSDF shader is the cornerstone of PBR workflows in the software. Let's break down its most important parameters:

Base Color

What it controls: The diffuse color of the surface – essentially what color the object appears to be.

Real-world equivalent: The pigment or dye in a material.

Best practices:

• Keep base colors in a believable range (avoid pure black or saturated colors)

• For metals, base color should be very dark or the color of the metal itself

• For non-metals, base color represents the actual color you see

Common values:

• Wood: Brown tones (RGB ~0.5, 0.25, 0.1)

• Skin: Various tones (RGB ~0.8, 0.6, 0.5)

• Plastic: Any color, but slightly desaturated

• Concrete: Neutral gray (RGB ~0.5, 0.5, 0.5)

Metallic

What it controls: Determines whether the material behaves like a metal or a non-metal (dielectric).

Real-world equivalent: The electronic configuration of the material that defines how it conducts electricity and reflects light.

Best practices:

• Use binary values (0 or 1) for most materials

• 0 for non-metals (plastic, wood, skin)

• 1 for metals (steel, gold, aluminum)

• Intermediate values (0.3-0.7) only for special cases like dirty or oxidized metals

Technical note: Metals absorb all refracted light and convert it to heat, which is why they have no subsurface scattering and their reflections take on the color of the base color.

Roughness

What it controls: How smooth or rough a surface appears, affecting how light scatters when reflected.

Real-world equivalent: The microscopic imperfections on a surface.

Best practices:

• No real-world surface has a roughness of exactly 0 or 1

• Most materials fall between 0.1 and 0.8

• Roughness affects the sharpness of reflections

• Consider surface treatment (polishing, wear, etc.)

Common values:

• Polished metal: 0.1-0.2

• Clean plastic: 0.2-0.4

• Finished wood: 0.4-0.6

• Concrete: 0.7-0.9

Specular

What it controls: The intensity of reflections on non-metallic surfaces.

Real-world equivalent: The index of refraction (IOR) that determines what percentage of light reflects off a surface.

Best practices:

• For most non-metals, keep between 0.3-0.5 (default 0.5 is ~IOR 1.5)

• Increase for materials like wet surfaces or glass (0.5-1.0)

• Has minimal effect on metals (metallic = 1)

Technical note: Specular reflection is the mirror-like reflection of light, as opposed to diffuse reflection where light is scattered in all directions.

IOR (Index of Refraction)

What it controls: How light bends when passing through transparent materials.

Real-world equivalent: The physical property that determines how much light slows down and changes direction when entering a material.

Common values:

• Air: 1.0

• Water: 1.33

• Glass: 1.5-1.7

• Diamond: 2.417

Best practices:

• Only relevant for transparent materials

• Higher values create stronger reflections at glancing angles

• Works in conjunction with transmission settings

Transmission

What it controls: How much light passes through the material.

Real-world equivalent: Transparency or translucency of a material.

Best practices:

• 0 for opaque materials

• 1 for completely transparent materials

• Use with IOR for accurate glass, water, etc.

• The Transmission setting affects both direct light and background visibility

Subsurface Scattering

What it controls: How light penetrates and scatters within a material before exiting.

Real-world equivalent: The phenomenon where light enters a material, bounces around inside, and exits at a different point, creating a soft, diffused look.

Best practices:

• Essential for organic materials (skin, wax, food)

• The Subsurface Radius controls how far light travels within the material

• Set different radius values per color channel for more realistic results

• For skin, slightly higher radius in red channel and lower in blue

Sheen

What it controls: Soft, velvet-like reflection at grazing angles.

Real-world equivalent: The fuzzy surface of fabrics like velvet, cloth, or microfiber.

Best practices:

• Use for fabrics, especially those with small fibers

• Often combined with some roughness

• Sheen Tint can add subtle color variations to the sheen effect

Clearcoat

What it controls: An additional layer of reflective coating on top of the base material.

Real-world equivalent: Varnish on wood, clear coat on car paint, or glazing on ceramics.

Best practices:

• Use values between 0.3-1.0 depending on coating thickness

• Adjust Clearcoat Roughness independently for worn or textured coatings

• Particularly useful for automotive paints and lacquered surfaces

Emission

What it controls: Light emitted by the material itself.

Real-world equivalent: Self-illuminating materials like neon, LED, or glowing objects.

Best practices:

• Use emissive materials as light sources (enable in Material settings)

• Color determines the hue of the emitted light

• Strength controls intensity (can go well above 1.0)

• Best combined with an actual light for realistic scene illumination