I did a search through the code for “Niagara Set Vector Array” and it came up, but the target would have gotten me there faster if I had looked at the doc.
What I was looking for was something more direct to call though. While it’s not bad or wrong to call those blueprint library functions from C++, in many cases they only exist for blueprint and there’s a more direct and clearer way to do it in native. Like you’d never call (made up example) int = ULibrary::Add( a, b );, you’d just do int = a + b;. But in this case the best thing seemed to be to use the library from native as well (though I’m not a graphics or Niagara guru so there still might be a better way).