Repair ribbon hole
The intention of those mini tutorials is to have simply searchable reference for the implementation of primary concepts in Niagara.
Immediately I need to have a fast take a look at how we’d resolve a typical challenge when utilizing Ribbons.
Except you spawn a particle each single body, there’ll at all times be a niche between the supply of the ribbon and the ribbon itself.
Spawning a particle each body, generally is a answer in some circumstances, nevertheless it’s typically higher to discover a answer in which you’ll be able to bridge that hole
There are a couple of methods to take care of this, however I’d wish to current a reasonably primary one that can work in a lot of conditions.
Primary Setup
The technique right here will probably be to reliably discover the final spawned particle and snap it to our supply location (the emitter place on this instance).
We do that by, for each particle, evaluating the index of that particle with the whole variety of particles which were spawned within the emitter. Within the case that we do have the final spawned particle, we set the Place of the particle to the simulation place.
Now to know the whole variety of particles we nonetheless must hold monitor of that one way or the other.
To do that, we’ll regulate the SpawnPerUnit and SpawnRate modules. (You’ll in all probability need to create a replica for this.)
On the finish of the modules we will add slightly part that reads the spawn rely and provides it to Emitter.TotalParticlesSpawned.
And increase now the final particle of your ribbon will stay hooked up to the supply.
Besides that’s not fully the case.
As a result of tick order it’s potential that this script will probably be executed earlier than the motion script of the supply.
This will create a one body hole between the final particle and the supply.
We will resolve this on a case by case foundation, by forcing the Niagara Tick to later within the body.
That is usually in poor health suggested as a result of it takes away the engines capability to utilize threading in an environment friendly means, but when used sparingly it may be useful.
And there you go, a fairly sturdy solution to make your ribbons gap-less.
Get pleasure from.
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After GPU Ribbon is obtainable to Niagara I’m not too bothered with this challenge, however I nonetheless need to share a much less correct however barely simpler answer to the hole challenge when utilizing Spawn Fee.
This method assumes the consumer to stay with a relentless spawn price worth, as a result of there’s little or no level of randomizing the spawn price worth each body in a ribbon emitter. Anyway as a result of the spawn price worth is fixed, we will merely calculate the spawn interval in second by 1/SpawnRateValue, then in Particle Replace stage, do a Lerp Place and select between SimulationPosition and Particles.Preliminary.Place (or simply Particles.Place is dependent upon your use case) by checking if the Particles.Age is smaller than the spawn interval.
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@ifurkend Humorous sufficient, somebody asking how one can do your described technique for spawn per unit, is what triggered me to search for the offered technique.
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If we’re speaking about the identical man, he truly wished the latest particle to transcend the actor place, which is feasible with our strategies, nevertheless it saddens me that it not issues now (not due to the GPU ribbon).
That is truly the identical technique as Partikel’s tip proper, simply not achieved in scratchpad 
and thanks for the good tip as nicely Niels!
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I’ve a query, as a result of I’m unable to learn what’s earlier than this (or extra like they’re too superior!), what does SpawnOutputInfo return? To my understanding, it appears you’re taking out the each rely of particle spawn and accumulate them to the Emitter.TotalParticlesSpawned.
It might be nice when you might clarify extra about this half, thanks.
it appears you’re taking out the each rely of particle spawn and accumulate them to the Emitter.TotalParticlesSpawned.
Yup, that’s precisely what we’re doing.
Spawn information is the construction a spawn module passes onto the engine to point that it desires to spawn new particles.
Should you open up one of many epic supplied spawn modules, you’ll discover that the final node in these modules is the one I marked in white.
So we merely copy the epic present modules and put these nodes within the image behind it to examine what number of particles this modules desires to spawn and add it to our rely.
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Hi there Niels!
I attempted your tutorial however for the second half (fixing the spawn price or spawn per unit) when compiling the module script it tells me there’s errors :
I’m undecided what to do since two of them are positioned on nodes that got here from the fundamental spawn price module. The final one is the map set on the finish (the one you add) however I suppose this error is brought on by the 2 others errors.
Are you able to assist me please ?
Chances are high your module utilization flags haven’t been set solely to emitter.
I discovered this challenge when spawning with the hole repair. Particles aren’t distributed evenly accross the path, I suppose it’s associated to delta time. How do you recommend to repair this?
If you need equal spacing, you should use a variation that snaps again the particle to it’s authentic spawn place as soon as it’s not the final one.
Hello, sorry for my late anwser however after attempting to vary my module utilization I get a number of issues :Even by clearing the namespace I nonetheless get the error (screenshot present what it was earlier than):
for the second because the node was not the identical as yours I take away the half within the center however no success in clearing the error both :
For the final one the flags are good so I don’t perceive the error right here :
I copy/paste the spawn price module from epic recreation so I don’t know the place I did one thing incorrect.
Doesn’t look good to me, it’s set as a particle module within the utilization flags.
You’ll need solely Emitter spawn and Emitter Replace
