MiniMax H3 swaps characters while keeping every move and shot intact.

Who it's for: creators who want this pipeline in ComfyUI without assembling nodes from scratch. Not for: one-click results with zero tuning - you still choose inputs, prompts, and settings.

Open preloaded workflow on RunComfy

Open preloaded workflow on RunComfy (browser)

Why RunComfy first
- Fewer missing-node surprises - run the graph in a managed environment before you mirror it locally.
- Quick GPU tryout - useful if your local VRAM or install time is the bottleneck.
- Matches the published JSON - the zip follows the same runnable workflow you can open on RunComfy.

When downloading for local ComfyUI makes sense - you want full control over models on disk, batch scripting, or offline runs.

How to use (local ComfyUI)
1. Load inputs (images/video/audio) in the marked loader nodes.
2. Set prompts, resolution, and seeds; start with a short test run.
3. Export from the Save / Write nodes shown in the graph.

Expectations - First run may pull large weights; cloud runs may require a free RunComfy account.

Overview

Replace a person or character in your video. Guide the new identity with a reference image. Keep the original motion and camera timing. Use SAM3 masks for precise subject control. MiniMax H3 maintains appearance across frames. Create clean swaps and outfit variations faster.

Important nodes:

Key nodes in Comfyui MiniMax H3 Character Replacement ComfyUI workflow

MiniMaxH3ReferenceToVideo (#464)

Central to identity transfer. It accepts a replacement image, a motion‑preserving video reference, and optional reference audio, then emits both the positive conditioning and an initial latent. Useful parameters to consider are prompt, width, height, and length. If you supply multiple references, keep them visually consistent to avoid identity drift.

SAM3_Detect (#503)

Finds and segments the on‑screen subject that will be replaced. A short category prompt via CLIPTextEncode (#502) guides detection. Adjust the mask quality options only when the default selection misses the subject or includes background; cleaner masks typically yield more stable swaps.

ImageCompositeMasked (#454)

Builds a performer‑focused reference from the sliced frames and SAM3 mask. Use x, y, and resize_source only if you need to align overlays or adapt frame scaling before sending images to the H3 reference input. The goal is a motion cue that isolates the actor while leaving scene geometry untouched.

ResolutionSelector (#501)

Controls the target render size in a few clicks. Choose an aspect and megapixel budget that fit your hardware or turnaround needs. Start modest, confirm identity stability, then increase resolution for your final pass.

SamplerCustomAdvanced (#469)

Executes denoising using the scheduler, sampler, guider, noise, and starting latent. For faster look‑dev, try a lighter schedule or a sampler tuned for speed, then switch to your preferred quality settings once identity and timing look right.

Notes

MiniMax H3 Character Replacement ComfyUI | SAM3 Ref2VA - see RunComfy page for the latest node requirements.