Repair ribbon hole
The intention of those mini tutorials is to have simply searchable reference for the implementation of primary concepts in Niagara.
In the present day I wish to have a fast have a look at how we’d resolve a typical challenge when utilizing Ribbons.
Until you spawn a particle each single body, there’ll at all times be a spot between the supply of the ribbon and the ribbon itself.
Spawning a particle each body, generally is a resolution in some instances, however it’s usually higher to discover a resolution in which you’ll be able to bridge that hole
There are a couple of methods to take care of this, however I’d prefer to current a reasonably primary one that may work in a lot of conditions.
Fundamental Setup
The technique right here shall 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 entire 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 entire variety of particles we nonetheless must preserve monitor of that by some means.
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 just a little part that reads the spawn depend and provides it to Emitter.TotalParticlesSpawned.
And growth now the final particle of your ribbon will stay hooked up to the supply.
Besides that’s not fully the case.
As a consequence of tick order it’s doable that this script shall 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 typically unwell 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 sturdy option to make your ribbons gap-less.
Get pleasure from.
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After GPU Ribbon is accessible to Niagara I’m not too bothered with this challenge, however I nonetheless wish to share a much less correct however barely simpler resolution to the hole challenge when utilizing Spawn Charge.
This method assumes the consumer to stay with a continuing 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 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 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 technique for spawn per unit, is what triggered me to search for the introduced technique.
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If we’re speaking about the identical man, he truly wished the most recent particle to transcend the actor place, which is feasible with our strategies, however 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 executed in scratchpad 
and thanks for the good tip as properly Niels!
