Script interface for the External Forces module.
See Also: ParticleSystem, ParticleSystem.externalForces.
| enabled | Enable/disable the External Forces module. | 
| influenceFilter | Apply all Force Fields belonging to a matching layer to this Particle System. | 
| multiplier | Multiplies the magnitude of applied external forces. | 
| IsAffectedBy | Determines whether any particles are inside the influence of a Force Field. |