VariationNoiseDetailerHookProvider

The simplest of Impact Pack's detailer hooks: two inputs, one job. VariationNoiseDetailerHookProvider builds a DETAILER_HOOK that applies a variation seed to the detailer's refine pass - the same idea as the "variation strength" slider some UIs expose on generation, but scoped to a detail pass instead of the whole image. Per the README: "Apply variation seed to the detailer. It can be applied in multiple stages through combine."

Where NoiseInjectionDetailerHookProvider schedules noise strength across a detailer's cycles, this one is a flatter, simpler operation - a fixed-strength nudge toward a different seed, applied once per region rather than ramped.

How it works

seed sets the variation seed, and strength (0–1) controls how much that seed's noise blends into the region's own noise during the detail pass. At strength: 0 you get nothing - the detailer behaves exactly as it would without the hook. Push it up and the region's output starts drifting toward what that alternate seed would have produced, without fully replacing your main seed's result. Because it's a DETAILER_HOOK, it applies per-region, per-detailer-run, not globally.

The README's note that it "can be applied in multiple stages through combine" means exactly what it sounds like: chain more than one VariationNoiseDetailerHookProvider - each with a different seed and/or strength - through DetailerHookCombine if you want a layered effect rather than a single variation nudge.

The inputs and output

• seed (default 0) - the variation seed to blend toward.
• strength (default 0, range 0–1, step 0.01) - how much that variation blends in. Default is 0, meaning this hook does nothing until you raise it.

Output is a single DETAILER_HOOK - wire it into a detailer's detailer_hook input, or into DetailerHookCombine alongside other hooks (or additional variation hooks at different seeds) first.

How to install it

Via ComfyUI Manager: search ComfyUI Impact Pack, install, restart. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/ltdrdata/ComfyUI-Impact-Pack comfyui-impact-pack
cd comfyui-impact-pack
python -m pip install -r requirements.txt   # ComfyUI's python; python_embeded on portable

then restart. No models, no extra dependencies - this one's pure noise-blend logic, nothing external to install beyond the base pack.

Common issues & troubleshooting

No visible effect. Check strength isn't still at its default of 0 - this hook is inert until you raise it above zero.

Detailed regions came out too different from the main pass. strength is too high, or you're layering multiple variation hooks through DetailerHookCombine and the cumulative effect is stronger than any single one looks like on its own. Bring individual strengths down, or drop to a single hook.

Every region with this hook looks similar to each other, not varied. Give each region - or each combined hook - a genuinely different seed, not the same one repeated. A shared seed produces a shared drift direction, not distinct variation.

Not sure you need this. Most detail passes don't. Reach for it specifically when a detailer's output on multiple regions looks too uniform or repetitive and you want a controlled amount of per-region variety, without the complexity of a full noise-injection schedule (NoiseInjectionDetailerHookProvider).