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Say I am trying to create a particle system that looks like a water hose which is spraying water particles in the direction that the hose is aiming. When I rotate the hose, the water particles would to change the direction they are moving to align with the direction of the hose, so they look like they are coming out of the hose, in the direction that the hose is aiming. Also when I move the hose around quickly, the water particles would also inherent the speed of the hose, and continue moving in the direction the hose is moving.

I am unable to achieve this effect in UE4, and no-matter which way the parent emitter is facing, or moving, they always emit in the same direction, and appear rigid.

Thanks for any help on this!
by phong (320 points)

1 Answer

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Best answer


it looks like your velocity is setup in world space ? I created a simple FX having a worldspace acceleration (Accel field used by the Physics evolver) to simulate gravity, and a velocity at particle spawn that is going to inherit the parent object's transforms, including rotation (see the attached screenshots shows the different transformation flags). This FX, once attached to an actor will react correctly to the actor's rotation.

You can download the package here and try if this works on your end, if not this might be another issue.

Let us know how it goes,

Thanks !

by HugoPKFX (17.7k points)
Great, thanks Hugo! This is great, I'm really enjoying Popcorn FX so far.
Hugo, that worked for the velocity direction. The second part of the question though, I could still use some help with. To put it another way, is there a way to do something like the 'Inherent Parent Velocity' module in Cascade?
You can have your particles inherit the effect instance velocity by selecting a particle layer and setting the "InheritInitialVelocity" to a non-zero value :

you will also need a physics evolver for this to work.
Thanks Julien, that is what I was looking for.