2🐕Seam Mask Generator

If you've used ergouzi's local-repair workflow - crop a region, run it through something, paste it back over the original - you already know the fix itself is rarely the hard part. The hard part is the edge. Composite a processed patch back into an image and you almost always get a visible ring where the two meet: a slightly different grain, a color step, a soft halo that gives the whole thing away. Seam Mask Generator exists to fix that ring and nothing else.

It's a small, single-purpose tool. Feed it the mask you used to define your repair region, and it hands back a new mask that isolates just the boundary band around that shape, not the whole filled area. That band is what you actually want to feather - blur or blend right at the seam, and leave the interior of your patch and the untouched background both alone. It's the same instinct the wider inpainting world settled on with dedicated crop-and-stitch tooling: don't touch anything outside the mask, and be deliberate about the pixels right at the edge. This is ergouzi's own take on that idea, built to work with its own crop/stitch nodes.

What you actually set

• senerate_width - how wide the boundary band is, from 1 to 666 pixels. That ceiling is way past what you'd use for a normal soft-edge blend (ordinary feathering usually lives in the single-digit-to-low-teens range), which tells you this isn't a one-shot blur radius - it's meant to generate a real region you then feed into further masking or blend work.
• smooth (on by default) - softens the band's own edges instead of leaving them hard-cut, which matters if you're going to threshold or composite with it downstream.

Both are required, along with the source mask. The single output is a mask - wire it wherever your composite step expects a blend mask.

Installing it

Through ComfyUI Manager: search "Comfyui-ergouzi-Nodes" and install. Or manually:

cd ComfyUI/custom_nodes
git clone https://github.com/11dogzi/Comfyui-ergouzi-Nodes.git

Restart ComfyUI afterward. No models to download - the whole pack is pure Python image/mask math, nothing here pulls weights off the internet. Worth knowing before you go looking for updates: the author says this English repo isn't being actively developed anymore. The newer, more complete version lives in a separate Chinese-first sibling repo. The node works fine as it is, you just shouldn't expect new features to land here.

Common issues & troubleshooting

The seam still shows up after using this. Usually means senerate_width is too small for the size of the patch you're blending - a 2-3px band barely registers against a large inserted region. Push it up before assuming the node isn't working.

The band doesn't line up with your actual patch edge. This happens when the mask you feed in doesn't match your image's resolution - if you resized the image after painting the mask, or the mask came from a different node with different dimensions, the seam band this generates will be offset from the real edge when you composite. Check mask and image dimensions match before wiring this in; it's the single most common way this kind of node "looks broken" when it isn't.

Beyond that there's not much to break - it's a pure mask transform with no external state, no file lookups, nothing that depends on what else is happening in your graph.