I have this Niagara particle system rendering sprites and a spotlight with its inner and outer cone angle the same. This should produce a hard edge light but on the particles there seems to be a fade.
The image below is what I’m getting, there should be no light outside of the spotlight cone.
Bah. 
Hmm…
Another wild guess here: You could unplug the base color from the material you are using for the Niagara smoke sprite and instead plug into emissive as the color. I believe emissive isn’t affected by light.
I’m not sure about the particles, but you could try setting the spotlight to movable if it isn’t already. There are a lot of situations where movable lights don’t scatter like stationary ones do.
That doesn’t seem to fix it, thanks for the input though
