Niagara / unreal GDC

Really cool bits of work dude!

Are any of the mesh modules on the GPU do you know? When I last checked everything mesh related was CPU bound I thought but was wondering if this had changed…

Hello everyone :slight_smile: I really like what I see on this forum! I’m not a VFX guy but lately I decided to give niagara a try. I really like it a lot. Here’s a demo sample of my tryout.

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Hey everyone!

So I’ve been toying around with Niagara and got some particles spawning behind a car as it drives around a track, but the issue I’m running into is when I deactivate the particle system all of the particles disappear at once, but I want to keep the already spawned particles alive so that they can complete their cycle. Am I possibly doing something wrong by just deactivating it with a BP?

Thanks!

I think (But im not totally certain if im right so apologies if not!) just deactivating via a BP just turns off / kills the particle system.

You’d want to reduce the spawn rate to 0 - then after a delay (which would be the lifetime of your particles) deactivate the PS.

So once all particles have died, deactivate.

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There should be deactivate and destroy. Deactivate should stop all further spawning, but keeps the spawned particles alive. Destroy removes the particle system object.

After deactivating you can check the onSystemFinished delegate to figure out when to destroy I believe.

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Thank you for the replies,

The weird thing is, when I use destroy on my cascade systems it works fine, but when it comes to Niagara the destroy doesn’t do anything and I’m not sure what’s cause it, I’m currently using the deactivate, but if I switch it to a destroy in the exact same place, nothing seems to happen

I do wonder if this maybe a bug with Niagara or something that’s not properly implemented yet?

It could possibly be, but for now what I think I will do is just drive the particles using the spawn rate, it looks kinda silly to just have them disappear out of nowhere lol

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Hello again,
So I’ve been exploring Niagara and trying a few tutorials and tried to take my hand at doing something simple, but I still have no idea what I’m doing so I’m most likely doing something terribly wrong.

My goal is to simply have a particle hover up and down and what I’m trying to do is set the Z position on over a curve. Does anyone know what I’m doing terribly wrong here?

You have to sample the curve.

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Oh is that all I’m missing? Is that what you did in your intro tutorial? I’ll go check that again. Thank you!

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FYI: Unreal Engine Livestream - Niagara: What’s New - Feb 14 - Live from HQ

Feb 14th Edit: https://www.twitch.tv/videos/380599760?t=00h08m35s

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Experiment with hologram effect. More realistic volume effect with sprites

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Hey guys, - I’m taking a look at ribbons in Niagara, and cant get them to be smooth AND get nice movement, - I am continually spawning particles (one spawn, then next then next, etc.) Not creating static beams using bursts. As im trying to create a continually emitted line as such

Ive tried changing spawn rate / tessellation / spawn per unit, and various other things, any ideas? Seen this issue posted many times but no real general solution given, only solution that worked for specific use cases.

Perhaps I’m approaching it wrong too? as I’m not using the beam setup/ beam update as used by the content examples that get smooth ribbons

  • Note my lifetime as shown above is no longer random as I know that will cause some issues!:slight_smile:

When i sample static mesh, i wonder, how can i get world position offset from material?

I suspect you’re running into one of the fundamental problems of using ribbons, which is that once the particles are no longer uniformly spaced you start seeing overlaps and kinks. If you take any of the content example ribbon emitters and add a curl noise force to them you should see the same issues. The content examples look nice and smooth because they chose a situation where they could avoid this.

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