ConditioningZeroOut (Combine)

This node zeroes out a conditioning for the early part of sampling, then lets the real conditioning take over - all in one node instead of the three-node dance you'd otherwise wire up. It's a niche composition tool, and if you've ever chained ConditioningZeroOut → ConditioningSetTimestepRange → ConditioningCombine by hand, this collapses that whole pattern into a single box with one slider.

Why you'd zero out a prompt early

The trick sounds backwards until you've seen it work: for the first handful of steps, ignore the prompt (or the negative), and only start applying it once the rough composition has formed from the initial noise. Those earliest steps are where the model decides the broad layout - pose, framing, where the big shapes go. Letting conditioning slam in immediately can lock the composition into something rigid or repetitive; holding it back for a fraction of the run lets a more natural layout emerge, then the prompt steers the details.

You'll most often see it applied to the negative conditioning. A hard negative from step zero can fight the composition; zeroing it for the opening steps and phasing it in tends to give cleaner, less contorted results. It's the same family of idea as the guidance-interval tricks - guidance early on is often doing more harm than good.

The inputs

Refreshingly minimal:

• conditioning (CONDITIONING) in - the prompt (positive or negative) you want to hold back at the start.
• zero_out_end (default 0.1) - how long to keep it zeroed, as a fraction of the sampling run. 0.1 means "stay neutral for the first 10%, then apply normally." Bump it up for a longer neutral window, down toward 0 to barely delay.

Output is a single CONDITIONING that behaves as zeroed-then-real, wired straight into your sampler's positive or negative input.

Install

No models, no deps:

• ComfyUI Manager: search "ComfyUI-ppm", install, restart.
• Manual: cd ComfyUI/custom_nodes && git clone https://github.com/pamparamm/ComfyUI-ppm, then restart.

Honest take

This is a "small tweak, occasional payoff" node, not something to put in every workflow. The default 0.1 is a gentle amount and a fine place to start; the effect at that setting is subtle, which is by design. Push zero_out_end too high and you're effectively running a big chunk of the sample with no guidance at all, which drifts off-prompt - so nudge it, don't yank it.

The reason to prefer it over the manual three-node chain is just cleanliness: one node, one slider, less graph clutter, and it's harder to miswire. If you're already comfortable building the zero-out/timestep-range/combine pattern yourself, this doesn't do anything you can't - it just does it tidier. If you're not, this is the friendly version.

Where it genuinely helps: compositions that keep coming out stiff, cramped, or samey across seeds, where loosening the grip for the first few steps opens things up. Try it on the negative first, small window, fixed seed, and compare. If you see no difference you like, it's a no-op you can bypass - this node can't hurt output quality, worst case it's inert.

Pack rule: if it errors after a ComfyUI-ppm update, delete the node and re-add it.