SplitSigmas_motorway_edition

SplitSigmas is the step-index cousin of SplitSigmasDenoise. Instead of cutting your noise schedule at a denoise fraction, it cuts it at a step number - you say "step 10," it hands you the sigmas before step 10 and the sigmas from step 10 onward. This is the Motorway edition, so the schedule rides on the pipe under a key and both halves come back under keys.

For two-pass workflows this is often the more honest tool. A denoise fraction is relative to an unknown total; a step index is exact. If you know your sampler is going to run, say, 20 steps and you want the first 10 noisy and the last 10 refined with a different model, SplitSigmas with step=10 gives you precisely that - no arithmetic against an invisible schedule length. It's the tool you reach for when you want reproducibility over convenience.

What to set

• INPUT_sigmas_key (default sigmas) - the Motorway key holding the SIGMAS from a scheduler node.
• step (default 0, 0–10000) - the index in the schedule to split at. Steps before it go to high_sigmas, from it on go to low_sigmas. Default 0 puts everything on the low side, so don't leave it at 0 and wonder where your high half went.
• OUTPUT_high_sigmas_key (default high_sigmas) - the noisy segment.
• OUTPUT_low_sigmas_key (default low_sigmas) - the clean segment.

Output is the MOTORWAY with both halves stored. Wire high_sigmas into one SamplerCustom, low_sigmas into another, pass the latent through between them, and you've got a controlled two-stage custom sampling run.

Installing it

cd ComfyUI/custom_nodes
git clone https://github.com/agilly1989/ComfyUI_agilly1989_motorway

Restart; it's under agilly1989 Nodes → Motorway-ed → sampling → custom_sampling → sigmas. Manager has the pack too. No pip dependencies to worry about.

Where people get burned

The step you pick has to make sense for the actual length of your schedule. Set step=10 on a 20-step schedule and the split is a clean 10/10; set it on an 8-step schedule and the "high" half is the entire thing, the "low" half is nearly empty, and pass two does nothing. Know your scheduler's step count first.

And the universal Motorway gotcha: keys are case-sensitive and must match exactly. 'MotorwayClass' object has no attribute 'hash_' is this pack's way of saying a key you referenced isn't in the pipe. Also fair warning - the pack is an active beta, and the auto-generated motorway-ed nodes have been disabled in some releases, so if a pack update makes this node disappear from the menu, that's upstream churn, not a broken install.