素材拆分(带透明通道) / Sprite Splitter RGBA

RuiSpriteSplitterRGBA is the version of the sprite splitter that keeps your transparency. The plain Sprite Splitter crops each element out of a sheet and fills the transparent areas with white; this one does the same crop but also hands you each element's alpha channel as a mask, so you can rebuild genuinely transparent PNGs downstream. If you're extracting game characters, props, or icons that need clean transparent backgrounds, this is the node to reach for - the plain variant is for when you just want the shapes on a white card.

It shares its entire skeleton with the base splitter, and the same golden rule applies: it splits on the alpha channel. The input sheet must already have real transparency - meaning you run it on an RGBA image that came out of a background-removal node (BiRefNet, rembg, and friends - all of that context is in the KB's background-removal essay if you want the lay of the land). A white-background sheet with no alpha will come through as one single connected component, which is not the splitting you wanted.

How it works

Identical mechanism to the base node: threshold the alpha, run connected-component labeling, crop each element to its bounding box. The inputs are the same five:

• 图像 - the sheet, with transparency.
• 最小面积过滤（像素数） - drop components smaller than this (default 100).
• 裁剪边距 - padding around each crop (default 2).
• 排序方式 - output ordering (reading order, or by area).
• seed - cache-buster only, no effect on output.

The difference is the outputs:

• 图像列表 - the cropped RGB images, one per element.
• 遮罩列表 - the matching alpha masks, one per element. 1.0 = opaque, 0.0 = transparent.

The pack README suggests wiring the mask list into JoinImageWithAlpha-style nodes to rebuild transparent PNGs, which is exactly the right pattern: RGB from the first output, alpha from the second, and you've got a clean RGBA asset per sprite.

Installing it

Part of the RUI-Nodes pack ("Rui-Node🐶"). Install once via ComfyUI Manager (search "RUI-Nodes") or:

cd ComfyUI/custom_nodes
git clone https://github.com/rui40000/RUI-Nodes
cd RUI-Nodes
pip install -r requirements.txt

Restart after. Needs scipy for the component labeling - in the pack's requirements already.

Where people get burned

The same traps as its sibling, plus one more: if you wire the alpha masks into a compositor, remember they're already inverted to the convention that compositor expects - check one output visually before you build the whole pipeline. And the "sheet must have real alpha" rule applies twice here, because the whole point is preserving that alpha. A white-background sheet fails silently into one giant component, and no amount of knob-turning fixes it - cut the background out first. Overlapping elements still merge, so keep your source sprites separated.