BD Preview 3D

You've just spent five minutes generating a 3D asset and you want to know if it's a character or a melted candle. Exporting it, opening Blender, and importing again is a lot of ceremony for that question. BD Preview 3D is the shortcut: give it a path to any 3D file - FBX, GLB, OBJ, STL - and it renders the model right in ComfyUI's built-in interactive three.js viewer, where you can orbit, pan, and zoom. It's a look-don't-touch node, and that's exactly its job.

This one is the lightweight member of the BrainDead preview family. It takes a single model_path string and nothing else - no mesh socket, no options, no outputs. You wire it a file path produced by another node (the README mentions BD_AutoRigUEFN and BD_AnimRetarget, which emit FBX paths) or just type in any absolute path on disk. It's an output node, so ComfyUI always runs it, and the viewer shows the file you pointed it at.

Where it shines and where it doesn't

The killer feature is skeletal animation: FBX files with rigs show up with a timeline in the viewer, so you can scrub through animations right in the node panel. That's a genuinely handy check when you're working a rigging pipeline and want to sanity-check a retarget before committing to an export.

But note the sibling node - BD Mesh Preview (Thumbnails) - does the other preview job. If you have a TRIMESH_LIST of parts from CubePart or a single mesh in the graph and you want a labeled, color-coded contact sheet, that's the thumbnail node. BD Preview 3D is strictly the "load this file and spin it around" tool, and it's path-based rather than graph-based. If your mesh only exists as an in-graph TRIMESH and hasn't been written to disk yet, wire a save/export node first and feed this its output path.

Install & the usual caveats

It ships with the ComfyUI-BrainDead pack - Manager search "BrainDead", or clone + pip install -r requirements.txt into custom_nodes. It uses ComfyUI's native viewer infrastructure, so no extra dependencies beyond ComfyUI itself (it even imports trimesh with a graceful fallback), and the pack rides the newer V3 API, so keep ComfyUI current.

Honest expectations: the viewer is built for inspection, not for judging topology quality. Generated meshes look great spinning on screen and can still be triangle soup under the hood - the "extremely low-quality 3D assets" verdict from the community applies here as much as to any generation output. Use this node to check orientation, silhouette, and animation timing, and keep your real quality gate for the export step.