BD Atlas Pack

If you've ever hand-packed a sprite sheet in Photoshop and re-derived the UV rectangles by eye, you'll appreciate BD Atlas Pack. It takes a batch of images and tiles them into a single grid atlas - and hands you a JSON layout with the exact per-cell pixel and normalized-UV rects so a game engine (or a shader) can pull each cell back out without you doing math.

This is the node behind the pack's Atlas / Flipbook workflow. It's the kind of plumbing that only feels boring until you need it: viseme sheets for lip-sync (7 visemes into one 2048×1024 sheet), sprite flipbooks, or packing a character's part textures into a single map. The engine-facing detail that makes it worth using rather than hand-rolling is the layout output - game engines need those normalized UV rects, and getting them from a hand-packed sheet is a chore.

How the sources stack up

The node concatenates inputs in a fixed order: the batched images IMAGE first (each frame becomes one cell, in batch order), then the individual image_1 through image_8 slots, then masks - where mask[i] supplies the alpha for cell i. If a mask batch isn't wired, an RGBA image's own alpha is used; otherwise cells are opaque.

The inputs that matter

• columns / rows - both default to 0, meaning auto. Columns auto to roughly square (ceil(sqrt(count))); rows auto to ceil(count / columns) and expand if there aren't enough. Leave them at 0 and you get a sensible grid; set columns explicitly when you want a specific aspect ratio.
• cell_width / cell_height - 0 means "use the widest/tallest input." Set them to force a uniform cell.
• fit_mode - contain fits the whole image inside the cell and pads (no crop), cover center-crops the overflow, stretch ignores aspect. Contain is the safe default for sprites; cover is what you want for a uniform texture atlas where every cell must fill.
• padding and background_hex - padding pixels between cells and around the outer border; the mask atlas pad regions are always 0, so you never get bleed at the edges.
• order - row_major or column_major fill order.
• output_alpha - off by default (RGB atlas); flip it on and the atlas becomes RGBA with the mask atlas as its alpha channel.

Three outputs: the atlas IMAGE, a single-channel mask MASK, and the layout STRING (JSON with per-cell pixel rects + normalized UV rects). Wire the layout into anything that consumes text, or save it as a sidecar.

Install

Standard pack install - ComfyUI Manager → search "BrainDead", or:

cd ComfyUI/custom_nodes
git clone https://github.com/BizaNator/ComfyUI-BrainDead
cd ComfyUI-BrainDead
pip install -r requirements.txt

Restart and it's under 🧠BrainDead/Segmentation. Like everything in this pack it needs a ComfyUI recent enough for the V3 node API. This one is pure tensor work - no models, no Blender - so it's a zero-drama node to slot into a bigger pipeline.

A practical note if you're packing game textures: pair it with the pack's BD_MaskFlatten (Voronoi alpha bleed for UV edge seams) and BD_CropAndCenter (common pivot per part) upstream, and what you pack will actually line up in-engine instead of bleeding or drifting. Atlas is only the last mile - the parts need to be prepared before they hit the grid.