---
title: "metalness(_:)"
framework: charts
role: symbol
role_heading: Instance Method
path: "charts/chart3dcontent/metalness(_:)"
---

# metalness(_:)

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

## Declaration

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

```

## Parameters

- `ratio`: The degree of metalness.

## Discussion

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).