---
title: SCNParticleModifierStage.postCollision
framework: scenekit
role: symbol
role_heading: Case
path: scenekit/scnparticlemodifierstage/postcollision
---

# SCNParticleModifierStage.postCollision

The stage after SceneKit simulates the results of collisions between particles and scene geometry.

## Declaration

```swift
case postCollision
```

## Discussion

Discussion Insert a modifier block at this stage to alter the output of collision resolution. For example, if you modify the velocities of particles during this stage, the modified velocities override the bounce velocity determined by SceneKit’s simulation.

## See Also

### Constants

- [SCNParticleModifierStage.preDynamics](scenekit/scnparticlemodifierstage/predynamics.md)
- [SCNParticleModifierStage.postDynamics](scenekit/scnparticlemodifierstage/postdynamics.md)
- [SCNParticleModifierStage.preCollision](scenekit/scnparticlemodifierstage/precollision.md)