---
title: FFENVELOPE
framework: Force Feedback
role: symbol
role_heading: Structure
platforms: [Mac Catalyst 13.0+, macOS 10.2+]
path: forcefeedback/ffenvelope
---

# FFENVELOPE

Used by the FFEFFECT structure to specify the optional envelope parameters for an effect.

## Declaration

```swift
struct FFENVELOPE
```

## Overview

Overview The sustain level for the envelope is represented by the dwMagnitude member of the FFPERIODIC structure and the lMagnitude member of the FFCONSTANTFORCE structure. The sustain time is represented by dwDuration member of the FFEFFECT structure

## Topics

### Initializers

- [init()](forcefeedback/ffenvelope/init().md)
- [init(dwSize:dwAttackLevel:dwAttackTime:dwFadeLevel:dwFadeTime:)](forcefeedback/ffenvelope/init(dwsize:dwattacklevel:dwattacktime:dwfadelevel:dwfadetime:).md)

### Instance Properties

- [dwAttackLevel](forcefeedback/ffenvelope/dwattacklevel.md)
- [dwAttackTime](forcefeedback/ffenvelope/dwattacktime.md)
- [dwFadeLevel](forcefeedback/ffenvelope/dwfadelevel.md)
- [dwFadeTime](forcefeedback/ffenvelope/dwfadetime.md)
- [dwSize](forcefeedback/ffenvelope/dwsize.md)

## Relationships

### Conforms To

- [BitwiseCopyable](swift/bitwisecopyable.md)
- [Sendable](swift/sendable.md)

## See Also

### Data Types

- [FFCAPABILITIES](forcefeedback/ffcapabilities.md)
- [FFCONDITION](forcefeedback/ffcondition.md)
- [FFCONSTANTFORCE](forcefeedback/ffconstantforce.md)
- [FFCUSTOMFORCE](forcefeedback/ffcustomforce.md)
- [FFEFFECT](forcefeedback/ffeffect.md)
- [FFEFFESCAPE](forcefeedback/ffeffescape.md)
- [FFPERIODIC](forcefeedback/ffperiodic.md)
- [FFRAMPFORCE](forcefeedback/fframpforce.md)