Unity Particle System, Emission Module, rate Over Time modify via script ...

Hello,

Please help me.

I've been dealing with this problem for about a week now, have read a lot and searched with google, but there are always compiler errors.

So far I've been able to solve all the problems myself, but this time I just can't.

I am using "Unity 2020.3.1f1" for my project, I am writing a script that should control the sequence in the current scene. The constant emission value "rateOverTime" should be changed with the script at a certain point in time. Unfortunately it doesn't work ...

However, the script should not be attached to the Particle System, but is located in an empty game object.

I even tried the example from the Unity documentation for the EmissionModule 2020.3, which also produces a compiler error.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
private ParticleSystem ps;
public float emissionrate = 1.0f;

void Start()
{
ps = GetComponent<ParticleSystem>();
}

void Update()
{
var emission = ps.emission;
emission.rateOverTime = emissionrate;
}
}

Then the error comes ...

NullReferenceException: Do not create your own module instances, get them from a ParticleSystem instance
UnityEngine.ParticleSystem+EmissionModule.set_rateOverTime (UnityEngine.ParticleSystem+MinMaxCurve value) (at <ac4201de60e7407889b38ca75ea7dc7e>:0)
SceneMainController.Update () (at Assets/Scripts/SceneMainController.cs:44)

I left the name of my Particle System as "Particle System", but I want to rename it to "vfx_fog".

best regards
Kasi

Please take this into account in your answers.

 

hi, i think you need to use the main module to acceed to Ps properties.

https://docs.unity3d.com/ScriptReference/ParticleSystem-main.html

 

oh , its about emission for you. a simple surch and you find this

https://docs.unity3d.com/ScriptRefe...16.483535752.1620715425-1879611349.1620461408

 

First of all, thank you very much for the quick answer.

But I've already tried it all in different versions and none of it works, unfortunately.

Unity has changed the syntax / command structure a lot since the 2020 version. And that's why nothing that could be found on google worked so far, unfortunately.

Unity may not have updated their documentation.

 

Code (CSharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using UnityEngine.UI;
6. using TMPro;
7.  
8. public class SceneMainController : MonoBehaviour
9. {
10.  
11.     float size = 0f;
12.     float readsize;
13.     public TMP_Text TextComponent;
14.     private float timer = 0;
15.     private float timerMax = 0;
16.     private ParticleSystem ps;
17.     public float emissionrate = 1.0f;
18.  
19.  
20.  
21.     // Start is called before the first frame update
22.     void Start()
23.     {
24.         Screen.sleepTimeout = (int)0f;
25.         Screen.sleepTimeout = SleepTimeout.NeverSleep;
26.  
27.         readsize = TextComponent.fontSize;
28.         TextComponent.fontSize = 0f;
29.  
30.         ps = GetComponent<ParticleSystem>();
31.  
32.  
33.     }
34.  
35.     // Update is called once per frame
36.     void Update()
37.     {
38.        
39.         if (!Waited(5)) return;
40.  
41.  
42.         var emission = ps.emission;
43.         emission.rateOverTime = emissionrate;
44.  
45.  
46.         if (!Waited(5)) return;
47.  
48.         if (size < readsize)
49.         {
50.             size = size + 0.5f;
51.             TextComponent.fontSize = size;
52.         }
53.  
54.         else
55.         {
56.             return;
57.         }
58.  
59.  
60.     }
61.  
62.     private bool Waited(float seconds)
63.     {
64.         timerMax = seconds;
65.  
66.         timer += Time.deltaTime;
67.  
68.         if (timer >= timerMax)
69.         {
70.             return true; //max reached - waited x - seconds
71.         }
72.  
73.         return false;
74.     }
75. }
76.  

 

NullReferenceException: Do not create your own module instances, get them from a ParticleSystem instance
UnityEngine.ParticleSystem+EmissionModule.set_rateOverTime (UnityEngine.ParticleSystem+MinMaxCurve value) (at <ac4201de60e7407889b38ca75ea7dc7e>:0)

Then the error message comes at the point where I want to address the emissions module.

 

Not sure where it's going wrong but the code above should NOT cause that special nullref error.

That error comes from trying to new up your own module, rather than access the one in the particlesystem, which your code seems to do.

Strip everything out, put this Start() function in a script, put it on a GO with a PS, and run:

Code (csharp):

1.     void Start ()
2.     {
3.         // make sure there IS a particle system on this GAmeObject!
4.         ParticleSystem ps = GetComponent<ParticleSystem>();
5.         float emissionrate = 1000f;
6.         var emission = ps.emission;
7.         emission.rateOverTime = emissionrate;
8.     }

 

Many many thanks.

 

Faced the same problem and... Wait what? Do I have to "ensure" this by calling "GetComponent()" every single time when I reference a particle system? Why it's not enough to do this only once in "Start()", for example? Why setting through the reference with inspector does not work?

 

Yes indeed "Wait what?" You apparently completely misread the remainder of my post. Spicoli would be proud!

It actually IS adequate to do it once in Start(), as I noted above and as my sample code shows.

Source: I do it all the time, whenever I don't feel like using the inspector to drag stuff in.

This works ALL DAY LONG for the ParticleSystem. You still must get the emission module in code.

Source: I do it all the time, when I'm not using GetComponent<T>()

 

Then why topic starter got the error when he did exactly this: got ParticleSystem in Start() and then used local variables for referencing its module in Update()?

 

Probably because he had another bug.

For one, he named his class ExampleClass:

For two, at the end of the day he certainly sounded happy after my post:

Go ask Kasi! I can't read his mind.

I stand by everything I wrote above.

 

Wouldn't this only set "var emission" equal to whatever the particles already doing? It doesnt assign the variable back onto the particle system at any point there from the looks of things. How would I get ps.emission to become var emission after? there's no way it just 'knows' to use that variable

 

Rather than asking cryptic "knows" questions against ancient posts that are looooong-ago closed...

PLEASE start your own post if you have an issue.

When you post, make it complete. We cannot read your mind. Here's a short checklist and how-to:

How to report your problem productively in the Unity3D forums:

http://plbm.com/?p=220

This is the bare minimum of information to report:

- what you want
- what you tried
- what you expected to happen
- what actually happened, log output, variable values, and especially any errors you see
- links to documentation you used to cross-check your work (CRITICAL!!!)

Don't TALK about code. Copy/paste and POST the code, ONLY the relevant code, and then refer to it in your discussion.

If you post a code snippet, ALWAYS USE CODE TAGS:

How to use code tags: https://forum.unity.com/threads/using-code-tags-properly.143875/