Help with Soft/Blurry refraction in UE


I need some help implementing refraction into my VFXs in UE4.

Been beating my head against this one for a while, since I’ve always attempted to add some amount of refraction to my other VFX but I never got it working properly and in this case, a black hole, it’s pretty much a requirement.

Case in point: I want to make a refraction “swirl” for this black hole VFX which is an ambient VFX i’ve been working on for my game.
Game GIF below:
(Screen capture - 6dfca40af343c638f0c2fbc2913a258b - Gyazo)

Reference would be the very soft refraction which occurs on league’s black holes:

How would I got about creating a very soft refraction like the examples above?
Is there a cheap way to fake refraction?
Or is there some other kind of trickery going on?

Thank you in advance!

1 Like


This could be a simple way for instance:
-the lerp controls the intensity of the refraction from 1 to 1.33
(I used a radial gradient but a black and white texture would work as well)
-and IIRC you need a normal map (because most likely you use camera facing particle)

plug that into a particle and you got it!


Sorry for the late response!!

Thank you, I’ll try it out and share the results soon.

Once again, thank you!
After tweaking with some values I was able to get very nice results with the black hole:

Ingame I get weird results, most likely due to the camera angle and the normal map, any tips on a possible fix? (Tweaking the camera angle is a no-no due to the gameplay)

Well, Idk how your camera moves.
But I’m guessing you used the distortion material on a camera facing particle(s)?
If you move your camera this big particles might be clipping with you environment (if it’s too close)

One simple fix would be to push the black hole down, to avoid clipping.
You also can use it a up-facing mesh/particle (up as in world space) so it doesn’t rotate anymore.

Also small tip, when using distortion add a camera offset node to the particle emitter and play with the distance to the camera.

1 Like