Question Add velocity additively in ParticleSystem.Emit

Hello, I've been trying to add a velocity to the particles I emit in particleSystem.Emit()

I have been trying three methods so far to achieve this, sadly none of them worked out:

1: To use the "Inhertit Velocity" module and give the particle system a kinematic rigidbody that I change the velocity of before emitting. This did not change anything even though a Debug.Log tells me that the rigidbody velocity has changed - I guess its because the particle system emits after the rigidbody notices its kinematic and resets the velocity to 0 again? When setting it to non-kinematic this creates glitchy movement of particles where they sometimes use the velocity and sometimes seemingly dont. It also does not work if multiple particles are emitted in 1 frame as they will use the same velocity in the end.

2: I tried to use the "Velocity Over Lifetime" module, but this will also have all already emitted particles change their velocity

3: When using velocity = X in the emit params, the velocity of other modules is overwritten completely

Does anyone have an idea on how to do this?
My use case is, if an enemy gets hit, I want to emit a particle effect that uses their velocity at the start so they dont just spawn and stay in the air, but move in the direction that enemy moved in when they got hit.
Maybe there is a start velocity parameter I am not able to find?

 

Thank you very much for your quick support, I am actually doing that already, I should have explained it better:

Code (CSharp):

1. ParticleSystem.ShapeModule shape = effect.particleSystem.shape;
2. shape.rotation = rotationToPlayEffectAt.eulerAngles;
3. effect.particleSystem.Emit(new ParticleSystem.EmitParams
4. {
5. position = positionToPlayEffectAt,
6. applyShapeToPosition = true,
7. }, 1);

This is my setup right now. I want to additively apply the velocity, so it uses the shape module and adds the velocity on top - similar to how it would behave if I instantiated the particle system in local simulation space as a child of the object whichs velocity I am using.



Is something like this possible?

 

I accidentally posted an unfinished reply trying to reformat my pasted code with tab tab space lol. Now I have to write everything again xD

This seems to work almost, but the velocity of the emitted particles is still wrong - or maybe not, but the rotation isn't working I believe. What does multiplying the quaternions do, I dont quite understand this part. I am using a cone shape on my particle systems.

I've been thinking if maybe interpolating between both rotations based on the velocityToAdd percentage of both velocities combines could help, but if the velocity to add had a near 100% percentage, the cone would be rotated too much, and - in case of the cube examble above would emit inside the cube.

This is my code now:

Code (CSharp):

1. ParticleSystem.ShapeModule shape = effect.particleSystem.shape;
2.         ParticleSystem.MainModule main = effect.particleSystem.main;
3.  
4.         if (velocityToGiveEffect != Vector3.zero)
5.         {
6.             shape.rotation = (rotationToPlayEffectAt * Quaternion.LookRotation(velocityToGiveEffect)).eulerAngles;
7.             main.startSpeedMultiplier = velocityToGiveEffect.magnitude;
8.         }
9.         else
10.         {
11.             shape.rotation = rotationToPlayEffectAt.eulerAngles;
12.             main.startSpeedMultiplier = 1;
13.         }

Also using startSpeedMultiplier changes the second value I am using in startSpeed set to randomBetweenTwoConstants

Thanks a lot for your help! If helping to solve this problem is too much work - It is not that important in my game, most if not all games dont really care about this, but I thought it would be nice to have. But maybe this is just not possible to do?