😺NKD Noise

Plain random noise is static - it reads as TV snow, not atmosphere. What clouds, fog, smoke and organic textures want is structured noise: big soft features with finer detail layered on top, which is exactly what fractal Brownian motion (fBm) produces. 😺NKD Noise generates fBm procedurally as an image and a mask, and - the part that makes it more than a texture generator - it animates over a frame batch and loops seamlessly.

The knobs

The fBm vocabulary is standard, and the defaults are sane places to start:

• scale - feature count across the frame; higher = smaller, busier features. 6 is a middle-of-the-road cloud-like setting.
• detail - fractal octaves; more = finer detail. 4 is a good balance.
• roughness - how much each finer octave contributes. 0.5 is neutral; higher roughens, lower smooths.
• lacunarity - the frequency step between octaves. 2 is the classic value.
• distortion - domain warp; swirls the pattern for an organic look. This is the knob that turns "clouds" into "smoke."
• contrast / brightness - shape the output's tonal range.
• offset_x / offset_y - pan the field.
• seed - same seed, same field.

The animation trio is where it gets interesting: frames sets the batch length (>1 makes an animated sequence), evolution moves the field across frames (the 4D time dimension), and loop makes the last frame flow back into the first over frames - a seamless loop, which is what you want for a background fog that cycles without a visible jump.

The optional mask input confines the noise to a region, feathered by its values.

Outputs

image - the noise as a grayscale image. And mask, which is the same field as a mask. Both, because the two uses rarely overlap: an image you composite over a scene as atmosphere, a mask you use to drive something else (a gradient map, a composite weight, a paint-in region). The author's own suggestion is to feed the output into 😺NKD Gradient Map to tint it - the fBm field becomes the brightness structure, and the ramp becomes the color, which gives you tinted fog or a colored smoke plume without any sampling.

Install and gotchas

Install via ComfyUI Manager (search ComfyUI-NKD-Basic-Tools) or:

cd ComfyUI/custom_nodes
git clone https://github.com/Nekodificador/ComfyUI-NKD-Basic-Tools

Restart after. Pack dependencies are onnxruntime and huggingface_hub; neither is needed here - this node is pure CPU math, no model, no download. The one thing that trips people up is scale intuition: scale is inverse (higher = smaller features), so if you expect big clouds and get grit, move scale down, not up. And loop only does its thing when frames > 1 - a single frame is trivially seamless and the setting is a no-op.