Roughness (PBR)
A material property that controls how sharp or blurry reflections are, from mirror polished to fully matte.
Roughness on a scale
In PBR materials roughness runs from 0 to 1.
| Finish | Typical roughness |
|---|---|
| Mirror polish | close to 0 |
| High polish jewelry | about 0.05 to 0.15 |
| Satin or brushed | about 0.25 to 0.45 |
| Sandblasted or matte | about 0.5 and above |
These are starting points, not standards, and different renderers interpret the value slightly differently.
Why it matters for jewelry
Most fine jewelry is highly polished, so its look depends on crisp reflections of the environment. A roughness that is too high makes a polished ring look like plated plastic. A roughness that is too low on a satin piece makes it look polished in the image and disappointing in the hand.
Mixed finishes
Many designs combine finishes, such as a polished bezel and a brushed shank. Put each finish on its own layer in CAD so each can get its own material. Directional finishes such as brushing may also need UV mapping or a dedicated material to show their grain.
In the studio
Metal presets in the studio come with roughness already set for their finish, so a polished preset stays polished in any environment. If a piece looks too dull, check the finish of the preset before changing the lighting.