---
title: "ParticleEmitterComponent.ParticleEmitter.ParticleColor.evolving(start:end:)"
framework: realitykit
role: symbol
role_heading: Case
path: "realitykit/particleemittercomponent/particleemitter/particlecolor/evolving(start:end:)"
---

# ParticleEmitterComponent.ParticleEmitter.ParticleColor.evolving(start:end:)

The particle’s color will start at the start color and transition over its lifetime to the end color.

## Declaration

```swift
case evolving(start: ParticleEmitterComponent.ParticleEmitter.ParticleColor.ColorValue, end: ParticleEmitterComponent.ParticleEmitter.ParticleColor.ColorValue)
```