SAM 3D Body: Export Multiple FBX

SAM3DBodyExportFBX handles one rigged mesh at a time. SAM3DBodyExportMultipleFBX is the version built for output from SAM3DBodyProcessMultiple - a whole group of reconstructed people, rigged and written out in one pass instead of one export node per person. If you ran a group photo through the multi-person pipeline, this is where you take the result out of ComfyUI.

How it works

It takes the bundled multi-person mesh data and runs the same UniRig-derived rigging pass that the single-person SAM3DBodyExportFBX uses, once per person in the bundle. The combine toggle decides what you get at the end: leave it on (the default) and everyone lands in one FBX file together; turn it off if you'd rather handle each person as a separate file - useful if you're feeding them into different pipelines or only want to keep some of them.

The inputs and outputs that matter

• multi_mesh_data (SAM3D_MULTI_OUTPUT) - required, and specifically the multi-person type. This only comes from SAM3DBodyProcessMultiple; the single-person Process nodes produce SAM3D_OUTPUT instead, which this node won't accept.
• output_filename (default sam3d_multi_rigged.fbx) - the export target.
• combine (default true, BOOLEAN) - the one setting worth thinking about before you hit run. All-in-one-file versus separate-files-per-person is a real fork depending on what you're doing next: character pipelines that treat each person independently usually want it off, quick group-scene mockups usually want it on.

One output: fbx_path (STRING) - the resulting file path (or, depending on how combine resolves, potentially the location the set of files was written to).

How to install it

Comes with the pack - via ComfyUI Manager, search SAM3DBody, install, restart. Manual path:

cd ComfyUI/custom_nodes
git clone https://github.com/PozzettiAndrea/ComfyUI-SAM3DBody.git
cd ComfyUI-SAM3DBody
pip install -r requirements.txt --upgrade
python install.py

Same rigging dependency as the single-person FBX export - this node is doing the Blender-derived rig-building pass multiple times over, so expect it to run slower than a single export, scaling roughly with how many people were in the source photo.

Common issues & troubleshooting

Rigs come out disconnected or mirrored, same as the single-person export. These are reported issues with the FBX rigging pipeline generally, not specific to the multi-person path - if you hit broken bone hierarchies here, it's the same underlying rigging step as SAM3DBodyExportFBX, just run once per person.

Export is slow for a group photo. Expected, and scales with headcount - five people means roughly five rigging passes. If you only actually need one or two people out of a larger group, it's often faster to re-run SAM3DBodyProcessMultiple with fewer masks than to export everyone and discard what you don't need.

Wrong input type error. Double-check you're feeding multi_mesh_data from SAM3DBodyProcessMultiple, not mesh_data from a single-person Process node - the types aren't interchangeable, and this node specifically wants the multi-person bundle.

Not sure whether combine is doing what you want. If your downstream tool expects one file with multiple rigs versus several separate character files, check that assumption against actual output before building a larger batch pipeline around it - this is exactly the kind of setting worth testing on a two-person photo before you run it against a twelve-person group shot.