UNET To CKPT Converter

Some nodes are picky about what you call things. rgthree's Context node - the one that bundles a dozen connections into a single wire - has an input literally named ckpt_name, and it wants a checkpoint filename. But if you're running a modern setup, the thing you actually loaded might be a diffusion/UNET model from models/diffusion_models, not a checkpoint from models/checkpoints. The names don't match, the socket doesn't connect, and the workflow sulks.

UNET To CKPT Converter is the bridge. You pick a diffusion model from a dropdown and it hands you the filename labeled CKPT_NAME, ready to plug into exactly that socket. It's a naming shim, nothing more, and it exists because "checkpoint" stopped being the only way to get a model a few years back.

How it works

The node lists folder_paths.get_filename_list("diffusion_models"), so the dropdown is populated from ComfyUI/models/diffusion_models/ (and whatever else that folder path maps to). Select a file, and the node's one function returns that same string back out, labeled CKPT_NAME, typed as a * wildcard so it can connect to combo slots and any-type inputs.

That's the whole mechanism: in, out, renamed. The model itself is never loaded or touched - this node only moves a filename around. The actual loading still happens downstream in whatever node you wired it into.

The one output that matters

CKPT_NAME (*) is the entire output surface. Feed it into the ckpt_name input of an RGTHREE_CONTEXT node, or anywhere else that expects a checkpoint name but where you're really routing a diffusion model's filename. If your context node also has a unet_name input, this is the sibling to MarSelectDiffusionModel, which outputs the same filename under both labels in one shot - choose that one when you need both sockets fed; this one when you only need the checkpoint-named output.

Installing it

It's part of MarwanDSAI/comfyui-mdsnodes, so install the pack once. Easiest via ComfyUI Manager: search "ComfyUI-MDSNodes", install, restart. Manual route:

cd ComfyUI/custom_nodes
git clone https://github.com/MarwanDSAI/comfyui-mdsnodes

Then restart ComfyUI. No pip step - the pack's requirements.txt is empty and it declares zero dependencies.

Gotchas

The dropdown only sees diffusion_models, which in modern ComfyUI covers both models/diffusion_models and models/unet - so your UNET files will show up. What it won't list is a checkpoint, so if your model lives in models/checkpoints, this is the wrong bridge. And since the node is a pass-through, an empty dropdown means an empty folder - drop a model file in and refresh. Beyond that, there's not much to trip on: it's a filename with a costume change, and that's the whole job.