Mask Gaussian Region

The README puts it in five words: "apply a Gaussian blur to the mask." That's the entire node, and it's also one of the most useful ones in WAS's mask toolkit, because a hard-edged mask is one of the most common reasons an inpaint or composite looks obviously pasted-on. Mask Gaussian Region softens that edge with a standard blur, turning a razor 0-to-255 jump into a gradual falloff that reads as a natural blend instead of a cutout.

Why this is standard inpainting hygiene, not a nice-to-have

Modidex's own inpainting notes state the practical rule plainly: mask blur "softens the mask edges to blend generated content with the original," typical amounts run in the 4–12 pixel range, and the failure modes run in both directions - too little blur causes hard, visible seams, too much bleeds the edit into surrounding pixels you didn't mean to touch. Any hard-edged mask you build - a rectangle from Mask Rect Area, a raw SAM cutout, a color threshold - benefits from a pass through Gaussian Region before it goes anywhere near a compositing step. It's the single easiest fix for "why does my inpaint look pasted on."

How it works

A standard Gaussian blur convolution applied to the mask channel. Instead of blurring pixel colors the way you'd blur an image, it blurs mask values, so the transition between masked and unmasked area becomes a smooth gradient rather than a sharp edge. The heavier the blur, the wider and softer that transition band gets.

Distinguish it from Mask Smooth Region in the same pack: Smooth Region is about rounding off jagged, stair-stepped boundaries specifically - think blocky pixel-art edges getting rounded. Gaussian Region is a broader, heavier blur meant to create a genuine soft falloff for blending, not just to tidy up jagged pixels. If your mask edge is already smooth-shaped but hard-valued, Gaussian is the one that actually feathers it.

The inputs and outputs that matter

A MASK in, a blur amount controlling how far the softening reaches, and a MASK out with feathered edges. Light blur knocks the hard edge down while keeping the mask's shape essentially intact; heavy blur noticeably rounds and can shrink a small region's effective coverage, since blurring pulls values toward the average and a small white region surrounded by black loses peak intensity as a result.

Installing it

ComfyUI Manager: search "WAS Node Suite," install, restart. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/WASasquatch/was-node-suite-comfyui

install requirements.txt against your ComfyUI Python, restart. No model, pure image processing.

Common issues & troubleshooting

Still seeing a seam. Bump the blur amount - modidex's inpainting guidance puts a reasonable starting point around 4–12 pixels, but the right number scales with your resolution and how different the generated content is from the original. Also confirm whatever consumes the mask downstream actually respects soft values; some nodes threshold a mask back to strictly binary before using it, which throws away the feathering you just added.

A small masked region got fainter or vanished. That's blur pulling values toward the surrounding average - a small white spot on a large black field loses peak brightness fast under a heavy blur. Use a lighter amount on small regions, or reach for Mask Dilate Region first to give the region more area to survive the blur.

Whole pack won't import. Pack-level. WAS Node Suite has been unmaintained since the author marked it retired in December 2023; the recurring failure is the entire suite throwing "Import Failed" after a ComfyUI update from a pinned dependency clash. Reinstall requirements.txt against the correct, embedded Python interpreter and restart - this node itself has no external dependency to break.