SAM3 inverted-mask + MiniMax H3 workflow swaps characters in video, files shared
LordDarthShader · reddit · 2026-10-13
A Reddit user shared a ComfyUI character-swap workflow: SAM 3 generates a segmentation mask of the subject, the mask is color-inverted, and the masked video is fed to MiniMax H3's ref2video model alongside reference images of the author's dog — placing the Pomeranian into a Thriller-style zombie dance clip (see image).
Key takeaways:
- Building on earlier r/comfyui and Patrick Sheedy's H3 guides, the author found that black masks lose all facial information, while an inverted-color mask preserves it and yields much better results.
- Example prompt and the full workflow file are publicly linked in the post.
- The workflow includes a Character Lora node, disabled for this demo.
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