setting the spawn area of particles through blueprints

I’m trying to change the size of an area the particles spawn through blue prints. Ideally I’ll have a parameter value for Location>>initial location>>start location. The problem is that it uses a “distrubution vector uniform” which defines an area and the most a parameter can do is a vector. My only work around is to use Initial Location>>cylinder. Then adjust the rotation, radius and length. this is a pretty poor work around as there is not “Box” spawning area I could scale or adjust size with a vector.
If anyone has any ideas for a better work around it would be greatly appreciated.

One thing you might try is to scale the entire particle system itself in BP, using a Set World Scale 3D node. If this enlarges the individual particles too much, you can then use a corresponding vector parameter value to scale them back down.

Now, if the particle sizes are ALSO using distribution uniform… You’re out of luck. And FWIW I, too, wish there was a way to parametrize the individual bounds of a distribution parameter.

That is a very good idea. Thank you for the response.

Just bumping to say thanks to RhythmScript for the sanity there… I forgot about scaling in cascade there for a moment and was about to scale in the shader. One other thing to note is that the particle system needs to be set to Local Space for the 3D scale to affect the initial location.

I made a BP so I can visualize the spawn area better, and in the construction script if the emitter is scaled I adjust SizeScale (and RateScale) accordingly. Now I can spread rain splashes over various rectangular areas easily.

But the lack of Box Initial Location, or just a “Location Scale” module is a shame. I think on a previous project we coded in an “Affected by Emitter Scale” checkbox to all applicable modules, so we could pick and choose what the emitter scale did to a particular system.