BD Rig Preview

Auto-rigging a character is a leap of faith until you can see the skeleton. Did the armature come out with the shoulders where they should be? Is the spine actually following the mesh? BD Rig Preview is the BrainDead pack's answer to that moment: it renders a rigged FBX as a bone-visualization image - orange spheres at the joints, cylinders for the bones, and the character mesh floating over it as a semi-transparent ghost. You spot a misplaced joint before it costs you a failed export, not after.

What it is

An inspection node for rigs. You feed it an fbx_path - specifically the output of the pack's auto-rig nodes: BD AutoRig MIA, BD AutoRig UEFN, or BD MixamoToUEFN - and it returns a single preview IMAGE. No model loading, no sampling; it's a renderer for a file path.

How it works

It renders the FBX headlessly using Blender (the pack's BlenderNodeMixin shells out to a Blender executable). The render shows the bone hierarchy: joints as orange spheres, bones as cylinders, and the character mesh as a translucent overlay so you can judge how well the skeleton lines up with the surface. The controls are minimal and sensible:

• view_mode - all_views (default) produces a 2×2 grid of front/side/back/perspective, perfect for a quick overall check. Or pick a single view (perspective, front, side, back) for a full-resolution look at one side - useful when you suspect a specific area is off.
• mesh_opacity - 0 = bones only, 1 = fully opaque mesh; the tooltip's 0.2–0.35 recommendation is right, since you want to see the bones through the character, not fight the character for attention.
• resolution - per-view resolution (default 768; the 2×2 grid doubles it, so 768 → 1536×1536 output).

Output: preview (an IMAGE), which you wire to a PreviewImage node like any render.

Where it fits

The workflow it's built for: run an auto-rig node, then immediately preview the result before committing to export. Auto-riggers are impressive and imperfect - a badly-placed joint is exactly the kind of thing you only notice in a viewer, and by then you've already written the FBX. One render here catches it in seconds. There's no companion "BD Rig Edit" - this is a check, not a fix - so if the skeleton is wrong, you re-run the rig with better settings, which is precisely why the cheap preview pays for itself.

Gotchas

The one real requirement is Blender. This node renders via a headless Blender subprocess, and it needs a Blender executable to find. The README says Blender 5.0+ (bundled in the pack's lib/); the code actually searches a bundled copy, sibling packs like ComfyUI-GeometryPack / ComfyUI-UniRig, or a system install (/usr/bin/blender, etc.). If you get "Blender not found," the fix is installing Blender or the GeometryPack. On a headless Linux box that's a slightly bigger install, but it's a one-time cost. Also: it renders, it doesn't validate - a rig can render fine and still be broken in-engine, so treat the preview as a first pass, not a certification.

Installing it

ComfyUI Manager: search "BrainDead" → install. Manual:

cd ComfyUI/custom_nodes
git clone https://github.com/BizaNator/ComfyUI-BrainDead
cd ComfyUI-BrainDead
pip install -r requirements.txt

Restart, find it under 🧠BrainDead/AutoRig. Wire an fbx_path from a BD auto-rig node, hit run, and read the skeleton before you read the export logs.