---
title: particleMassVariation
framework: scenekit
role: symbol
role_heading: Instance Property
path: scenekit/scnparticlesystem/particlemassvariation
---

# particleMassVariation

The range, in kilograms, of randomized particle masses. Animatable.

## Declaration

```swift
var particleMassVariation: CGFloat { get set }
```

## Discussion

Discussion Setting a nonzero value for this property randomizes the effect of the particleMass property. SceneKit randomly adjusts the mass of each particle by up to half the particleMassVariation value. For example, if the particleMass value is 1.0 kilograms and the particleMassVariation value is 0.5 kilograms, each particle uses a random mass value between 0.75 and 1.25 kilograms for physics simulation. The default value is 0.0 kilograms, specifying no randomization. You can animate changes to this property’s value. See Animating SceneKit Content.

## See Also

### Simulating Physics for Particles

- [isAffectedByGravity](scenekit/scnparticlesystem/isaffectedbygravity.md)
- [isAffectedByPhysicsFields](scenekit/scnparticlesystem/isaffectedbyphysicsfields.md)
- [colliderNodes](scenekit/scnparticlesystem/collidernodes.md)
- [particleDiesOnCollision](scenekit/scnparticlesystem/particlediesoncollision.md)
- [acceleration](scenekit/scnparticlesystem/acceleration.md)
- [dampingFactor](scenekit/scnparticlesystem/dampingfactor.md)
- [particleMass](scenekit/scnparticlesystem/particlemass.md)
- [particleCharge](scenekit/scnparticlesystem/particlecharge.md)
- [particleChargeVariation](scenekit/scnparticlesystem/particlechargevariation.md)
- [particleBounce](scenekit/scnparticlesystem/particlebounce.md)
- [particleBounceVariation](scenekit/scnparticlesystem/particlebouncevariation.md)
- [particleFriction](scenekit/scnparticlesystem/particlefriction.md)
- [particleFrictionVariation](scenekit/scnparticlesystem/particlefrictionvariation.md)