Loop Strip — Assemble Sprite Strip

The name is the entire feature list. This node takes a batch of frames - the ones Loop Strip - Find Best Cycle just extracted for you - and glues them side by side into a single sprite strip you can save. That's it. It's the output stage of the pack, and it's about as complicated as the wrapper on a Snickers.

You can stitch frames together with a dozen other nodes, so why use this one? Because it's already the right shape for the pipeline, it does the one thing correctly, and there's no config to get wrong. If you're assembling a walk cycle or a character turnaround, this is the boring, reliable finish line.

How it works

The mechanism is trivial but worth knowing because it explains your output dimensions. A ComfyUI image batch is shaped [N, H, W, C] - N frames, each with its own height, width, and channels. The node concatenates along one axis:

• horizontal (default): frames are joined along the width. Eight 512px frames become one 4096px-wide image.
• vertical: joined along the height. Eight 512px frames stack into a 4096px-tall image.

Either way you get a single [1, H, W*N, C] or [1, H*N, W, C] image out of the strip output. It's flagged as an output node, meaning its only job is to feed a save - wire strip into a Save Image (or your favorite saver) and you're done.

The one input

Just frames and direction. A single dropdown, horizontal or vertical. Vertical is a legitimate choice for tall game sprites or if your horizontal width would blow past some tool's limit, but for classic side-scroller walk cycles you want horizontal.

Install

Via ComfyUI Manager, search "Loop Strip". Or the manual route:

cd ComfyUI/custom_nodes
git clone https://github.com/serhiiyashyn-sf/comfyui-loopstrip
cd comfyui-loopstrip
pip install -r requirements.txt

Restart ComfyUI after. The requirements (opencv-python, numpy, torch, scipy, requests) are the pack's standard set - nothing to download beyond the repo itself.

Gotchas, such as they are

The only real trap is the output resolution. A horizontal strip of 8 frames is one wide image, and ComfyUI's preview will happily try to render 4000+ pixels wide. That's fine for saving; it's only annoying in the UI, where you can zoom out. Don't mistake that for a broken output.

Also keep every frame the same size. If you're feeding this centered frames from Center Subject or Center Character, those come out uniform, so you're safe. If you ever feed it a raw batch with mixed dimensions, the cat will fail - so do your resizing upstream. Horizontal strips also keep working when your frames are RGBA (handy if you later want a transparent sprite), since it just joins the batches.

Thin, but honest: this is the node you reach for when your loop is found and your character is centered and you just want the sprite sheet on disk.