Base - Arnold User Guide
Color
The Base Color sets the albedo (fraction of light reflected per channel) of the diffuse and metallic base.
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| Red | Green | Blue |
Weight
Multiplies the albedo color of the base (dielectric or metal).
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| 0 | 0.5 | 1 |
Diffuse Roughness
The base component follows an Oren-Nayar reflection model with surface roughness. Zero roughness is equivalent to a Lambertian reflection. Higher values result in a rougher diffuse surface look that is more suitable for materials like concrete, plaster, or sand.
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| 0 (default) | 1 |
Base Metalness
Specifies how metallic the base material appears (dials the base from pure dielectric at 0.0 to pure metal at 1.0).
A Base Metalness of 0 produces a dielectric surface that can be used to model various non-metallic (opaque or translucent) materials:
- Diffuse: opaque internal media, e.g. wood, granite, concrete, cardboard, and wall-paint.
- Subsurface: dense highly scattering internal media, e.g. plastic, marble, skin, vegetation, and food.
- Transmission: translucent internal media, e.g. glass, crystals, and liquids.
While a Base Metalness of 1 produces a fully metallic, opaque material.
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| 0 (default) | 0.5 | 1 |
For a perfectly sharp and mirror-like reflection, increase Base Metalness to 1, and reduce the Specular Roughness to 0. The Base Color and Base Weight should also be set to 1.
When Base Metalness is enabled, the Specular Color controls the tint color near grazing angles, while Base Color controls the reflection color at normal incidence. Note that Specular Weight modulates the intensity of the entire metallic lobe, at both normal and grazing incidence.
The metal appearance is controlled using the Base Color (facing) and Specular Color ("F82" edge tint) parameters. Some examples of real-world values for metals are listed below.
| Base Color | Specular Color | |||
|---|---|---|---|---|
| Aluminium (Al) |  |
0.912 0.914 0.920 |  |
0.970 0.979 0.988 |
| Copper (Cu) |  |
0.926 0.721 0.504 |  |
0.996 0.957 0.823 |
| Gold (Au) |  |
0.944 0.776 0.373 |  |
0.998 0.981 0.751 |
| Iron (Fe) |  |
0.531 0.512 0.496 |  |
0.571 0.540 0.586 |
| Lead (Pb) |  |
0.632 0.626 0.641 |  |
0.803 0.808 0.862 |
| Mercury (Hg) |  |
0.781 0.779 0.779 |  |
0.879 0.910 0.941 |
| Nickel (Ni) |  |
0.649 0.610 0.541 |  |
0.797 0.801 0.789 |
| Platinum (Pt) |  |
0.679 0.642 0.588 |  |
0.785 0.789 0.784 |
| Silver (Ag) |  |
0.962 0.949 0.922 |  |
0.999 0.998 0.998 |
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| Aluminium | Copper | Gold |
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| Iron | Lead | Mercury |
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| Nickel | Platinum | Silver |
Info: You can use base Base Metalness values between 0.0 and 1.0 to texture surfaces like rusted iron, where different areas of the surface can have more reflective clean metal or more diffuse rust. You can connect PBR metalness maps from applications like Substance Painter to the Base Metalness parameter.
Rusted iron texture -> Base Metalness
