Particle System Distance Rate + RigidBody 2D

Hello !
I'm having an issue with the new Unity 5.5: my particle system doesn't emit over distance when not moved with physics if a rigidbody2D is attached to it (if I only do transform.Translate, it does Emit if my object does not have a rigidBody2D component attached), I don't know if I am the only one but it's troublesome !

If anyone have an idea on how to overcome this I'll be happy !

Thanks !

 

I see, I'll try this, thanks for the quick reply !

 

Hi,
For me it did not work to add the ParticleSystem as child to the RigidBody, but the other way round.
I use touch gestures to move a GameObject with RigidBody2D and ParticleSystem attached. The ParticleSystem emits over distance. This was broken in Unity 5.5.
I tried to make the ParticleSystem a child of the RigidBody2D as suggested above, but the emission still did not work. Now I moved the ParticleSystem back to the main GameoObject and made the RigidBody2D a child. This seems to work.
Hope this helps.

 

This tutorial example use to have tanks that threw dust when moving forward/backward. Now, since those changes, they only throw dust when turning: https://www.assetstore.unity3d.com/en/#!/content/46209

Since this change is made "by design": https://issuetracker.unity3d.com/is...not-non-kinematic-rigidbody-slash-rigidbody2d
It would be good to update the Manual: https://docs.unity3d.com/Manual/PartSysEmissionModule.html

 

Hi. I make the particle system a child of RigidBody, then move the RigidBody by using rigodBody.MovePositoin(), but the particle system still not work at all. I have to make the particle system "out of the RigidBody" (Not a child), and update its position in Update(), it works but this is not a good way to do like this. Is it any way to solve this?

 

Please check the attach file.
In the example scene, I made the particle system as a child of the rigidbody object, but the particle system didn't emit when its parent moving. (I made the rigidbody object moving by using "RigidBody.MovePosition()")
Thanks for help

 

Sorry for my late reply. I've reported a bug(900069). Thanks for your help.

 

This is actually a very old bug which first occurred in my project was about 3-4 months ago. My solution was has an empty container for the two objects separately has rigidbody and particle system attached. And then move the container. It works at first place but still doesn't make sense to me for a long time. So I googled this topic and hope this bug could be fixed asap.

 

Also currently going through the tank tutorial, and when moving the tank using "RigidBody.MovePosition()", the RB component reports a velocity of 0,0,0 when i poll it with debug log. Don't know why particles get spawned when rotating, but this depends on the particle object being off-center of the parent. If you reset xform on the particle child object, it will fail to spawn particles both when translating and rotating.

 

Hey guys,
I've sufffered with this problem when i've tried to update from 5.4 to 5.6, i'd searched through stack overflow and some other forums but nothing...
Then i've decided to solve it with the solution below.
This is happening because the particle system someway is being affected by dynamic rigidbody and it becomes directly dependent of the FPS(Try to decreace or increace and you will see it).
To resolve there are some ways, the last one is the most correct in my opinion.

1st, Create a particle that uses rate over distance out of the parent and make follow it.
(as i've made before like stylophone)

2nd, Put an Knematic not simulated (not affected by physics) rigidbody on the game object responsbile by the particle.



Before

After

.

 

In case you missed it:
https://moonflowercarnivore.tumblr.com/post/157945497336/rigid-body-and-particle-system

 

Oh, i didn't see it, but if i'm not wrog, you were changing the velocity of the gameobject to 0 on late update in your solution, right?. you were using an particle outside the rigidbody2d following target right?.
On 5.6 the boolean simulated it is in the inspector, in your video it wasn't.
(but still in doccumentation at least from 5.0)
In my specific case, i use addforce to move my spaceship, soo i would had to do it(make particles out of them following) my spaceship and a bunch of enemies it would flood the hierarchy, using as an child inside and rigidbody with an knematic not simulated it became more clean in my opinion for my situation.

 

I am not entirely sure about "changing the velocity of the gameobject to 0", but it is correct that my solution requires that the PS is not parented to any object with RB component. Because you're copying the world position (instead of local position) of the RB object to the target PS object, it doesn't matter where that PS object is positioned on awake.
The solution with "is knematic" was an answer I got from a Unity technician, may be Karl?
If emission over distance is functional but simply not perfectly as expected, you should instead enable any interpolation option in the RB component first.

 

Hey guys, sorry to resurrect this by a few months.

I was working my way through the Tanks! tutorial as well and ran into this dust trail problem. I solved it by setting the velocity as mentioned above. However, later on, when the exploding shell should have pushed the tank, it didn't work as expected. The tank just teleported a short distance rather than appearing to roll backward.

After reading karl jones' reply, I created another empty game object (called Dust) as a child of the Tank object. I then moved the two dust trail objects so that they were a child of Dust. I added a Rigidbody to Dust and checked "is Kinematic". This allows the dust trails to work and the tank to be pushed back as expected by the exploding shell.

This is probably not ideal, but it gets the same behavior as the tutorial without any script changes.

 

Totally right there, I had my missiles with rigidbodies because I was instantiating them as rigidbodies from code. Therefore the particle systems stopped working from Unity 5.5.0 up.
Now I removed the rigidbodies from the missiles prefabs and instantiate them as just as GameObjects. And the particles came back again.

 

i have had this same problem in 2021 (using unity 2019) and i read this thread and https://answers.unity.com/questions/1291371/unity-550-particle-system-emission-module-rate-ove.html

i found the described behavior logical but the solution(s) confusing.

what i did was this:

1. as a "bullet" i am having a particle effect with "emission: rate over distance" with non-kinematic rigidbody (parent). it worked well even though it has the above described situation.
2. i added a "homing" effect, by putting a Rigidbody.AddForce() in (Fixed)Update() which required me to set Rigidbody.Velocity() to zero or else my homing wouldnt work.
3. with this change the particle effect was lost (not emitting anything)
4. what i needed to do to solve it was now this:

rb.velocity = this.transform.forward * my_custom_speed * Time.fixedDeltaTime;

so as a summary: having the rigidbody was no problem. starting it with AddForce() was no problem. but adding homing effect with AddForce() in each FixedUpdate() AND setting velocity manually to zero (which is maybe stupid, i dont know, it just worked for me) caused the velocity to stay zero. setting the velocity manually worked, but only when i multiplied it by Time.fixedDeltaTime (because its a physics effect).

hope this helps someone else

feel free to tell me where my whole logic is stupid, i would love to learn to do it better