I’ve created a niagara system of leaves falling to the ground. The idea is that I want to put this on a tree, so the leaves look like they are falling from the tree. The problem is, if I spawn a particle system at every tree, I could have thousands of them. So I’ve been looking into niagara data channels. I got it working using the locations of the trees. The issue is that it will only spawn one burst of leaves from each tree unless I write to the data channel constantly. By constantly, I mean I’ve had to set up a timer that fires every second that just writes the same tree locations over and over again. This seems kind of strange that I have to do this. All of the examples I find online are people using it for one off events like impact effects. I can’t find any examples of just continuously running particle systems. Is that not what data channels are meant for (only discreet events?) or am I missing something?
If you want to use the data channel to spawn leaf particles then you need to write into the data channel for every spawn event. So for example all the tree positions you want to spawn from this frame.
But if your tree positions are fixed and should just spawn particles regularly, you could also use a position array as user parameter, set all of them once and then just randomly spawn particles from each of them as an ongoing effect.
I ended up just doing what you are saying about writing the tree positions every time I need to spawn particles on a timer as it doesn’t need to happen every frame. It appears to work fine, just feels strange. I do like your idea of setting an array of positions, except the tree positions are not 100% fixed. i.e. they can change at runtime from time to time. Also, I don’t see anyway of causing a particle system that is controlled by an NDC to spawn regularly on its own. That does not appear to be an option that I could find in the docs unless you can point me to something?