Fusion - How to create a vertical gradient for Waviness strength

[Robbbb]

Hi everyone,

I'm trying to create a smoke-like distortion effect in Fusion using the Waviness node.
What I’m aiming for is a vertical gradient in the strength of the effect:

• At the bottom of the rectangle → no waviness
• At the top → strong waviness

So the distortion gradually increases from bottom to top,
At the moment, the Waviness node applies the effect uniformly across the whole image, and I’m not sure what the best approach is to control its intensity based on position.

 

[Syxguns]

You can absolutely control the strength of the Waviness effect by position — you just need to feed it a gradient map. Waviness applies distortion uniformly by default because it has no built‑in falloff, so the trick is to give it a custom mask that tells it where to distort more or less.

The simplest way to do this is:

Use a vertical gradient as the strength map.​

Steps:

1. Add a Background node
2. Change it to a black‑to‑white vertical gradient
   • Black = no distortion
   • White = full distortion
3. Pipe that Background node into the Effect Mask / Strength Map input of the Waviness node
4. Adjust the gradient to control how quickly the distortion ramps up

This gives you exactly what you described: bottom = clean, top = smoky and distorted, with a smooth transition between.

If you want something more organic (actual smoke‑like breakup), you can take it a step further:

Optional: Add Fast Noise for texture​

• Create your vertical gradient
• Add a Fast Noise node (soft, low contrast)
• Combine them with a Multiply node
• Feed the result into the Waviness mask input

That gives you:

• A clean vertical falloff
• Plus natural turbulence from the noise
• Without losing control over where the distortion is strongest

But for a simple bottom‑to‑top ramp, the plain gradient alone is the cleanest solution.