Shuriken - inherit velocity doesn't work properly!

I have a Player character that is moved by adding forces to it's rigid body. I made sort of a flamethrower using particles from Unity 3.5 (not shuriken). I took a velocity vector from the player character every frame, and set the world velocity of the particles every frame. This way if the character is moving 100km/h forward, the particles don't stay behind him (even if in the real world they would ).

Right now I switched to Unity 4, and I'm trying to redo the flamethrower using shuriken. It is a better system in every way, except using "Inherit velocity" produces very strange and random results. Literally, the particles go in random directions when I change velocities of the player with controls. Instead of adding the player's world velocity to their local velocities they go crazy whenever I press a direction button.

I mean, most of the time they go in proper direction with proper velocity (inherited from player), but when I change the veloctiy with controls, 20% (more less) or sometimes all particles for 0,3-1s go in random direction. Mostly in world Z axis, but sometimes in X or Y.

Is that a bug?

 

Ok, no help. I tried everything, it's a bug. Well, switching back to old particle system... Looks a little bit worse, has no collisions, but it works.

 

I'm experiencing something quite similar.

I'm building an exhaust-flame from a spaceship with the Shuriken particle system. What I want to a achieve is that nice kind of bend in the flame when you turn. To do this the smoke and fire need to inherit the velocity of the craft. Else the flame will make a sharp angle, as opposed to the wanted bend, right at the engine exhaust.

It's just that the inherit velocity doesn't work properly. When I turn it on most particles will go the right way, backward, but a whole lot will be sent out in front of the craft or to the sides (when turning). The effect is worse at higher velocities.

I took a picture of the problem:


I use rigidbody and add forces to power the craft, could that cause such problems?

 

Who are you? Are you support, and if so why do you only have one post?
If you are support then please tell me what you mean with a bug report? I thought I just wrote one here!

 

A report has been submitted, hopefully the problem will be solved one way or another

 

I was wondering if my reply to bugs@unity3d.com came forward? It looks like the kind of mail you might not be able to send a reply to?

 

Bump, I lost contact after the first reply from support. I really would like someone to answer

 

Bump

 

I have exactly the same problem as Switchice. I am also building a spaceship and cannot get Inherit Velocity to work correctly.
At low speeds the particle system looks ok (not as good as in local simulation space, but ok). At higher speeds it looks really strange and also emits in the wrong direction.

 

I'm having the exact same trouble with the latest build (Unity 4.1.1f4) Causing me real problems with spray from a boat puffing in the opposite wrong direction at regular intervals just like Lorodion's picture. I wonder if this is a new problem or has always been there?

 

Seems to be still a problem in Unity 4.1.5f1, bug report submitted.

 

This has not been fixed yet as of version 4.3.0f4.
I have also sent a bug report to Unity so that they can fix this!

If anyone else wants to reproduce this, download my project from here: View attachment $unityShurikenBug.zip
Zoom/pan with the mouse, wait for a few seconds and you'll see the error appear.

 

Got a reply from the Unity team saying they're working on it, but there is no specific deadline: http://fogbugz.unity3d.com/default.asp?579166_diif38d16d87f1og

 

This issue still exists in 4.3.3

Also trying to do a spaceship thruster effect, and when I enable the effect, the first few particles emit with a completely wrong velocity. Then the effect behaves until I stop it and restart it - where it does the same thing

 

Has this really been a bug for a year and a half? It makes the particle system almost useless on any moving object. And there's no way to access most of the particle system via script? I could make this work if I could just set the initial velocity each frame in the script.

 

Still not fixed in 4.5

 

Are there any news on this bug? i'm having the same problems when trying to create tyre smoke for cars, most particles will behave as expected but a few will shoot ahead of the car. As other have noted the problem is more notable at high speeds.

 

Is there any progress on this bug ? I saw you wrote in another thread, inherit velocity at 1 should make the particle stick to the parent 100%. Currenty thats not how the inherit velocity works at all. It you put it to inherit velocity 1, the particle will fly off in all kinds of directions, depending on the speed you move. So, essentially you cant really do anything decent with inherit velocity right now. The only thing you can achieve right now is some movement to the world particles on a low value, but you don't really have any decent control over it. This bug has been existing now ever since Shuriken was released, and currently you cannot make any particle behvave like a tail or something similar to that. It's either world velocity where its stuck in the emitting space (with its local movement added) or its local and completely linked. So theres a lot of situations you have to find a certain workaround and never get the result you are aiming for.

Anyone found any workaround for this I would be very interested to hear. But most of all I wish Unity could fix this bug soon! I'm experiencing situations this is needed frequently.

 

I'm also having this problem and it's getting urgent for me. I have just submitted a bug myself - #619852 :

http://fogbugz.unity3d.com/default.asp?619852_46r7kule36neuqa6

The issue seems to occur when I call Play on the ParticleSystem after all existing particles from the last burst have expired - the first new particle released will often shoot off at an odd angle. If I set Inherit Velocity to 0 it fixes the issue completely, but any other value causes the glitch.

 

Any news here? Trying to decide if I should try to hack together a workaround.

 

I have found a work around for this! AFTER ALMOST ONE YEAR !
The problem seems to be that no changes to a Rigidbody or a GameObject are allowed to be done in the Update method or in a couroutine with WaitForEndOfFrame (or timed). Now when I use Rigidbodies I handle all forces in FixedUpdate and in coroutines with WaitForFixedUpdate and now everything works fine. If I have to move objects without a Rigidbody attached I do this in a coroutine after WaitForFixedUpdate (I simulate my own Update ).

 

Damn, Unity 5.1 and still nothing, this bug is known for more than 3 years! It seems it won`t be resolved than And unfortunately fixed update doesn`t resolve this one for me... My missiles will be looking bad. Bad Unity engineers, bad!

 

If anyone also want to get attention to this issue, here You can give Your vote to it:
http://issuetracker.unity3d.com/issues/shurikens-inherit-velocity-doesnt-work-properly

For me it is matter of engine choice, I like Unity, but if this issue won`t change till I start next project, I will be forced to change engine to something different than Unity unfortunately, so I do hope this will be resolved in time.

 

I'm thinking I have the same problem in Unity 5.1.2f1.
I have tried enabling interpolation on the parent object, put everything in fixedupdate, inherit velocity = 1.
When I use forces to move my parent object around I looks like the particle system is turning left/right before it's parent, which it is a child of. If I set simulation space to local the particles are emitted from the correct location but then it's kinda useless.

I wanted to vote on the issue but apparently it has been marked as fixed?

 

Also for me interpolation did nothing unfortunalty.

 

Funny thing to come back to Unity after 4½ years and STILL encounter this problem. @karl_jones anyone worked on this in the last year?

 

I've created a test scene to reproduce this. It contains a simple cube with a particle system (thruster) and constant acceleration in positive x. I added a "safe zone" script to loop the box within -1000 >= x >= 1000 to avoid floating point issues. There's also a script for the camera (to look at the cube) and a script to log the cube's velocity periodically.

This is what it looks like at start:


And this is what it looks like after some time (high velocity):


You can download the project here.
Just press play and you can see the action. At about a 100 units per second (velocity) you can see the thruster particles jumping out ahead of the cube and the full thruster system also jumps around violently.
Another thing is that the particle system gets elongated as time passes which is not realistic for particles that inherit the speed of an object with constant acceleration on a linear path.

Maybe I configured something wrong - if you got any suggestions on how to fix this @karl_jones let me know!

 

Hi.
Got another issue.

What happened with inherit velocity set to "current"? It worked I think in 5.5. I'am on 5.6.1f1 right now and setting inherit velocity to current does not work no matter the multiplier value. Initial works fine. Both emitters simulation space is set to world.

Is there any new trick to make it work? Documentation did not change a bit.

 

Sure thing.
Case no. 934429

 

This problem still exists in 2019.4.21f1 if you set mode initial for inherit velocity ... Very sad ...