SAM 3D Body: Preview Rigged Mesh

Opening a full 3D application just to check whether an FBX export actually worked is friction most people would rather skip. SAM3DBodyPreviewRiggedMesh renders your exported, rigged mesh right inside the ComfyUI graph - point it at a file path, and it shows you the result without leaving the browser. When it works, it's genuinely convenient. Worth knowing going in: this is also the node that generated the most "it's broken" reports on the pack's release thread.

How it works

It's a pure preview node - takes a path to an FBX file (typically one you just wrote with SAM3DBodyExportFBX or SAM3DBodyExportMultipleFBX) and renders it in-graph, rig included, so you can spot problems like a bad pose or a broken bone hierarchy before committing to opening Blender.

The input that matters

Just one: fbx_output_path (STRING, required). Wire it straight from SAM3DBodyExportFBX's fbx_path output, or from SAM3DBodySelectMesh if you're pointing at a file you exported in an earlier session. There's no output on this node at all - it's a terminal, display-only step in the graph, not something you chain further nodes off of.

How to install it

Comes bundled with the pack. Via ComfyUI Manager: search SAM3DBody, install, restart. Manual install:

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

No separate download for the preview itself - it's rendering a file you already have on disk, not fetching anything new.

Common issues & troubleshooting

"Error loading model." This is the single most-reported problem with the pack on release. Multiple people hit this exact message with this exact node, independent of each other, and it was still unresolved as of the release thread - the author's response each time was to ask for a GitHub issue, which suggests it wasn't a one-line fix at the time. If you hit it, check the pack's GitHub issues before assuming your setup is uniquely broken; there's a reasonable chance it's already tracked.

Nothing shows up, no error either. Double-check fbx_output_path is actually pointing at a file that exists and finished writing - if SAM3DBodyExportFBX is still running or errored silently upstream, this node has nothing valid to load.

The rig preview looks broken - bones disconnected, pose off. That's very likely reflecting the FBX itself rather than a preview bug. SAM3DBodyExportFBX has its own known issues with bones coming in unlinked; if the preview looks wrong, check the actual export in Blender to see whether the problem is in the file or specific to this preview node.

You'd rather just check the file yourself. If this node is being unreliable for you, opening the exported FBX directly in Blender is the fallback - a bit more friction, but it sidesteps whatever's causing the in-graph preview to error for some setups.