BD Blender Decimate

Plain decimation is easy - shrink a mesh to a target face count and watch every hard edge dissolve into mush. That's useless for stylized low-poly work, where the whole point is keeping clean silhouettes and crisp color seams at a fraction of the triangle count. BD Blender Decimate is BrainDead's full-featured answer: a Blender-based decimator that detects color boundaries and planar structure before it starts removing geometry, then preserves them as sharp/seam edges while it works.

The headline feature is the color_field input. This is the correct way to keep colors through decimation: wire a COLOR_FIELD (from BD_SampleVoxelgridColors or BD_UnpackBundle) directly into the node instead of pre-applying colors to the mesh. The pack is emphatic about why - pre-applied colors force faces to split at color seams, which destroys the topology you're trying to clean. Sampling colors spatially on clean topology, then preserving them during decimation, gives you a low-poly mesh where the colors and the hard edges actually agree.

The inputs that matter

• target_faces (default 5000) - the face budget. Everything else is in service of hitting this without wrecking the mesh.
• detect_color_edges (default on) + color_edge_threshold (0.15) - marks color boundaries as sharp/seam edges. Lower threshold = more edges preserved. This is the "CRITICAL" toggle in the pack's own docs.
• planar_angle (7°) and sharp_angle (14°) - the planar decimation merge angle and the post-decimation sharp-edge mark angle. Lower planar angle = flatter, more faithful surfaces.
• use_planar_grouping + planar_group_angle (15°) + planar_group_min_size - optional structure-aware grouping that finds planar regions from face normals and marks their boundaries.
• preserve_boundaries / preserve_colors - both on; preserve mesh borders and transfer colors with face-based lookup (no bleeding).
• remove_internal (+ internal_method SIMPLE/RAYCAST) - jacketing cleanup for hidden internal faces, off by default.

Optional: color_field (the star input), timeout, and debug_path to dump a debug GLB when you need to see what went wrong. Outputs: decimated mesh + status.

Install and the Blender gotcha

Pack install is standard - ComfyUI Manager → "BrainDead", or:

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

Restart, update ComfyUI (V3 API required), and - this being a Blender node - make sure a real Blender exists on the system. The README says it's bundled; the binary isn't in the repo. The code checks bundled blender-5.0.1, sibling packs, then /usr/bin/blender. No Blender, no decimation.

Where people get burned: they decimate to an aggressive target and blame the node when the silhouette wobbles - but the real fix is usually detect_color_edges + planar_grouping doing their job, or pre-running BD Blender Cleanup. For a quick stylized look, run this after BD Planar Grouping with straighten_boundaries=True, then finish with BD Blender Merge Planes. That's the pack's documented hard-edge pipeline, and it's genuinely good.