Does VFX Graph SendEvent support spawning a specific number of particles?

[v7342659018]

I am in a situation where I want to reuse a particle “burst” effect, and adjust the amount of particles in the burst.

Right now I have a pretty convoluted VFX Graph set up where I specify a custom int on a dummy particle, which then dies immediately and triggers a GPU event, which spawns the real particles.

I’ve noticed that if I set the lifetime of this dummy particle to something very low (0 or 0.01), in certain situations, no particles get spawned. But it’s not clear to me when this happens (it seems to happen at specific timings related to when other particles spawn and/or when the vfx graph is initialized… but not sure on this). Setting the life of the dummy particle to 0.1 seems to resolve this issue.

I’m wondering if there is a better way of spawning a specific number of particles, where this number is supplied through a C# script?

Here is my VFX graph for reference:

[v7342659018]

So after looking through the direct link example here:

New Feature : Direct Link

Hello, I would like to follow up on this thread and I think it’s more appropriate to centralize a message in a dedicated post. We have some updates about these limitations, we recently added the support of “Direct Link” event (see this merge request if you are interested about the implementation details). First thing first, this feature is mainly addressed to advanced users who want more control on spawn events. For instance, you can be a gameplay programmer who is triggering a really cust…

It turns out that spawnCount is actually a float, not a uint I guess the documentation isn’t updated, as it says spawnCount is a uint with a default value of (0,0,0)…

https://docs.unity3d.com/Packages/com.unity.visualeffectgraph@7.1/manual/Reference-Attributes.html

[OrsonFavrel]

@v7342659018

So after looking through the direct link example here:
https://discussions.unity.com/t/847493

It turns out that spawnCount is actually a float, not a uint I guess the documentation isn’t updated, as it says spawnCount is a uint with a default value of (0,0,0)…

https://docs.unity3d.com/Packages/com.unity.visualeffectgraph@7.1/manual/Reference-Attributes.html

Just wanted to let you know that “Direct Link” isn’t always needed and that you can use regular “exposed properties” to control the spawnCount of an effect.

This approach is simpler to setup, and you can also set your properties values with C#.
In the case of an Exposed Burst/SpawnRate, the VisualEffect.SetFloat("name", float); public method should do the trick

Have a great day.