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# metalness(_:)

A value that controls whether the surface has a metallic look.

```
nonisolated func metalness(_ ratio: Double) -> some Chart3DContent
```

## Parameters

`ratio`

the degree of metalness.

## Discussion

Zero represents a non-metallic (dielectric) surface.
One represents a metallic surface.
In real life, materials are either metallic or dielectric (0 or 1).

---

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