Repair ribbon hole
The intention of those mini tutorials is to have simply searchable reference for the implementation of primary concepts in Niagara.
At this time I wish to have a fast have a look at how we would resolve a standard situation when utilizing Ribbons.
Until you spawn a particle each single body, there’ll all the time be a niche between the supply of the ribbon and the ribbon itself.
Spawning a particle each body, generally is a resolution in some instances, nevertheless it’s usually higher to discover a resolution in which you’ll bridge that hole
There are a couple of methods to cope with this, however I’d prefer to current a reasonably primary one that may work in numerous conditions.
Primary Setup
The technique right here can 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 overall 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 overall variety of particles we nonetheless must maintain monitor of that in some way.
To do that, we’ll modify the SpawnPerUnit and SpawnRate modules. (You’ll in all probability wish to create a duplicate for this.)
On the finish of the modules we are able to add somewhat part that reads the spawn rely and provides it to Emitter.TotalParticlesSpawned.
And increase now the final particle of your ribbon will stay connected to the supply.
Besides that’s not solely the case.
Because of tick order it’s potential that this script can 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 usually in poor health suggested as a result of it takes away the engines skill to utilize threading in an environment friendly means, but when used sparingly it may be useful.
And there you go, a fairly strong option 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 situation, however I nonetheless wish to share a much less correct however barely simpler resolution to the hole situation when utilizing Spawn Fee.
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 are able to 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 how you can do your described methodology for spawn per unit, is what triggered me to search for the offered methodology.
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If we’re speaking about the identical man, he really needed the most recent 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 really the identical methodology as Partikel’s tip proper, simply not finished in scratchpad 
and thanks for the good tip as effectively 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 could be nice if you happen to 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 data is the construction a spawn module passes onto the engine to point that it desires to spawn new particles.
When 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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Whats up 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 undecided what to do since two of them are situated 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 attributable to the 2 others errors.
Are you able to assist me please ?
Likelihood is your module utilization flags haven’t been set completely to emitter.
I discovered this situation 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’d like equal spacing, you need to use a variation that snaps again the particle to it’s authentic spawn place as soon as it’s not the final one.
