Repair ribbon hole
The intention of those mini tutorials is to have simply searchable reference for the implementation of primary concepts in Niagara.
Right this moment I need to have a fast take a look at how we’d resolve a typical concern 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 resolution in some circumstances, but it surely’s typically higher to discover a resolution in which you’ll be able to bridge that hole
There are just a few methods to take care of this, however I’d prefer to current a reasonably primary one that may work in numerous conditions.
Fundamental 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 have to hold observe of that one way or the other.
To do that, we’ll modify the SpawnPerUnit and SpawnRate modules. (You’ll most likely need to create a replica for this.)
On the finish of the modules we will add slightly part that reads the spawn depend and provides it to Emitter.TotalParticlesSpawned.
And growth now the final particle of your ribbon will stay connected to the supply.
Besides that’s not totally the case.
As a result of tick order it’s doable that this script will probably be executed earlier than the motion script of the supply.
This may 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 typically ailing suggested as a result of it takes away the engines means to utilize threading in an environment friendly approach, but when used sparingly it may be useful.
And there you go, a fairly strong strategy to make your ribbons gap-less.
Get pleasure from.
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After GPU Ribbon is on the market to Niagara I’m not too bothered with this concern, however I nonetheless need to share a much less correct however barely simpler resolution to the hole concern when utilizing Spawn Charge.
This method assumes the person to stay with a continuing spawn fee worth, as a result of there’s little or no level of randomizing the spawn fee worth each body in a ribbon emitter. Anyway as a result of the spawn fee 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 depends 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 easy methods to 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 needed the most recent particle to transcend the actor place, which is feasible with our strategies, but it surely 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 nice tip as properly 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 depend of particle spawn and accumulate them to the Emitter.TotalParticlesSpawned.
It will be nice should you might clarify extra about this half, thanks.
it appears you’re taking out the each depend of particle spawn and accumulate them to the Emitter.TotalParticlesSpawned.
Yup, that’s precisely what we’re doing.
Spawn data is the construction a spawn module passes onto the engine to point that it desires to spawn new particles.
For those who 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 test what number of particles this modules desires to spawn and add it to our depend.
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Hi there Niels!
I attempted your tutorial however for the second half (fixing the spawn fee or spawn per unit) when compiling the module script it tells me there’s errors :
I’m unsure what to do since two of them are positioned on nodes that got here from the essential spawn fee 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 ?
Likelihood is your module utilization flags haven’t been set completely to emitter.
