This must be right in front of me but I can’t find it…
I’d like to activate the visibility on each particle in the editor (like in the screenshot below).
(to avoid confusion, I’m referring the yellow little boxes surrounding the particles)
Sorry I’m not sure I fully understand your question.
If you are talking about turning on and off the entire emitter you can do this by ether getting a reference to it in your level blueprint or in any other blueprint and then do a set “visibility” or “toggle hidden”.
If you want to do it to just one sub emitter in a system try this.
First name that sub-emitter. Then get a reference to it in your level blueprint or other blueprint. Add that reference to the graph. Pull off that reference and search for “Enable Emitter”. In that function put the name of the sub-emitter you want to turn on or off. Trigger that function when you want it to turn on or off.
If you want each particle to turn on individually, I would just set a lifetime to the particles and set your spawn rate to your desired amount. If you need them to spawn in slowly you can set a low spawn rate with a high life time. But be careful as you need to make sure you don’t end up spawning more than you want. If you don’t want to start with just a few around at first you can go to the Particle system properties and set “Warmup Time” You can get to the particle system properties by clicking on the black space to the right of your sub emitters in cascade.
For small things like your particle here try using GPU particles they would be much cheaper and faster in this case.