ParticleSystem.ExternalForcesModule.influenceCount

Description

The number of Force Fields explicitly provided to the influencers list.

When influenceFilter is set to ParticleSystemGameObjectFilter.List then only Force Fields in the influencers list affect the Particle System.

Additional resources: ParticleSystemForceField.

using UnityEngine;

public class Example : MonoBehaviour
{
    ParticleSystem.ExternalForcesModule externalForcesModule;

    void Start()
    {
        // Create a default particle system
        var particleSystemGameObject = new GameObject("Particle System");
        var system = particleSystemGameObject.AddComponent<ParticleSystem>();

        // Create a force field to influence the particle system
        var forceFieldGameObject = new GameObject("Force Field");
        var forceField = forceFieldGameObject.AddComponent<ParticleSystemForceField>();
        forceField.endRange = 5;
        forceFieldGameObject.transform.position = new Vector3(0, 0, 10);

        // Add the force to the particle systems external forces influencers.
        externalForcesModule = system.externalForces;
        externalForcesModule.enabled = true;
        externalForcesModule.influenceFilter = ParticleSystemGameObjectFilter.List;
        externalForcesModule.AddInfluence(forceField);
    }

    void OnGUI()
    {
        GUILayout.Label("Particle System Influencers:");
        for (int i = 0; i < externalForcesModule.influenceCount; ++i)
        {
            var influence = externalForcesModule.GetInfluence(i);
            GUILayout.Label(i + ": " + influence.name);
        }
    }
}