Vehicle smoke emitter advice

Hi all again,

I was hoping you all could help out with a problem with emitting smoke from a fast moving vehicle.

I’ve tried quite a few solutions to the problem but I am hitting the issue of if its in local space then looks very strange in motion with the smoke not reacting or trailing with the movement or using non local it requires the particles to be a very short lifetime to look convincing and not create large trails behind a fast moving vehicle. Furthermore if I reduce the lifetime of the particles in non local space then they look pretty unconvincing when not moving.

My particle systems have the usual fast spawning setup etc (spawn per unit etc)

My options feel to me to be either:

  1. To assign the lifetime and other attributes that change through a blueprint dependent on speed
  2. Have a slower speed and faster speed variants which I blend between at a certain point

I just wanted to ask people of more experience if I am missing something really obvious here or is one of the above the way to go? Should I be making a smoke plume from a ribbon? That doesn’t seem viable to me…

Thanks again for reading this wall of text!

If you are spawning into world space, you can try inherent parent velocity. With this, you can apply all or some of the vehicles velocity to your particles.

I’d also recommend Aaron’s advice using Inherit Parent Velocity. Maybe have some short lived, fixed spawn rate smoke in local space (I’m assuming this is for a tail pipe, or a Rocket League style trail?) You can also have multiple emitters that use Spawn Per Unit, but set a different speed range for each emitter. That may give you a bit more control. Ex: some smoke will only spawn if the car is moving between 0-X units, and then have a different emitter with different velocity or behavior with the SPU set for X-Y units.

Awesome thanks both for your reply. I was playing about with inherit parent velocity yesterday and that was yielding better results. That is also interesting to hear about limiting different emitters for different speeds, didn’t realize Spawn Per Unit had that functionality. Thanks!

The effect I am working on currently are smokes\fires coming off damaged components on vehicles. So it needs to deal with static to very fast moving vehicle motion.

Again thanks all for the input!