Checkpoint Random Selector

Most people want their checkpoint to stay put. Checkpoint Random Selector is for the rare person who wants it to wander - but wander deterministically. It picks a random checkpoint from a category of your choosing, and the pick is stable for a set interval. Every hour (or whatever you set), the choice rolls over to a new model. Same run to run within that hour, different model on the hour.

Why would you want that? Two real uses. First, variation exploration: if you're running long batch queues and want your output to drift across a folder of checkpoints instead of staying locked to one style, this is the node. Second, if you're testing - "which of these 40 SDXL checkpoints gives me what I want?" - a rotation loop answers that question for you while you're not looking. It's the checkpoint side of the pack's whole randomization-for-exploration philosophy.

How it works

The key design decision is that the randomization is deterministic per interval, not per run. It hashes the current time bucket (category + the hour/minute block) into a seed, so the same model is picked for the whole interval no matter how many times the queue executes. That's why you don't get a different checkpoint every single generation - the node's IS_CHANGED only fires at interval boundaries, which is also how it stays ComfyUI-cache-friendly instead of dirtying the graph every step.

The inputs you actually touch:

• base_folder - root of your model folders. The default is D:/CODE/STABLEDIFFUSION_AUTO/models/Stable-diffusion, which is the author's Windows path. Change it to your own models/checkpoints folder or nothing will match.
• category - SDXL, PONY, or SD15, and the three *_folder_name fields tell it which subfolder each category lives in. It defaults to assuming you've got folders named like SDXL 10, Pony, SD15.
• interval_minutes - 1 to 1440, default 60.

safe_mode (default on) restricts to .safetensors/.sft; file_extensions is the override when it's off.

Outputs are strings, not a model: folder_path, file_path, and filename. That's the other gotcha - this node selects, it doesn't load. Wire the filename output into the pack's Checkpoint Loader By String Dirty (which does the loading and gives you model/clip/vae) to close the loop.

Installing it

Part of CorvaeOboro's ComfyUI_illumorae (CC0, pure code, no model downloads). ComfyUI Manager → search illumorae → install, or:

cd ComfyUI/custom_nodes
git clone https://github.com/CorvaeOboro/ComfyUI_illumorae

Common issues

• "No checkpoint files found" - almost always the default base_folder pointing at a path that doesn't exist on your machine. Point it at your actual checkpoints directory.
• It never changes. If interval_minutes is large you'll legitimately wait; but also remember it only rotates at interval boundaries - a run at 10:59 and a run at 11:00 are different models, two runs at 10:59 aren't.
• Model choice feels wrong - the selection is random, but if your category folders are misconfigured you might be sampling from a folder with one file in it. Check the folder_path output once to confirm where it's actually looking.