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

# roughness(_:)

A value that controls the degree of surface roughness.

## Declaration

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

```

## Parameters

- `ratio`: The degree of roughness.

## Discussion

Discussion Zero represents a smooth surface. One represents a completely rough surface.