BD Blender Edge Marking

Mesh tools have a bad habit of collapsing edges you wanted to keep. If you're doing stylized low-poly work, the fix isn't to fight the decimator - it's to tell the pipeline which edges matter before you run it. BD Blender Edge Marking does exactly that: it detects edges worth preserving - where colors change, where the surface angle changes - and marks them as sharp/seam/crease on the mesh, so downstream tools like BD Blender Merge Planes respect them.

The feature that makes it interesting for image-to-3D pipelines is color-based edge detection. A character's shirt-to-skin boundary is a color boundary, and if you mark those edges as sharp, they survive decimation and merging while flat interior regions get eaten away. That's how you get a clean low-poly character instead of a melted one.

Operations

• FROM_COLORS_AND_ANGLE (default) - marks edges where color changes or face angle does. The combined mode and the one you'll usually want.
• FROM_COLORS - color-change edges only. Controlled by color_threshold (0.15).
• FROM_ANGLE - dihedral angle edges only. Controlled by angle_threshold (30°).
• CLEAR - wipe existing sharp/crease marks.
• SHARP_TO_CREASE / CREASE_TO_SHARP - convert between mark types (handy for different downstream tools).

Plus mark_mode (ADD vs REPLACE), mark_type, crease_value, clear_sharp/clear_crease, and a generate_preview that outputs a visible wireframe of the marked edges as its own TRIMESH (preview_thickness controls the tube size).

The warning that matters

The node's docs carry a big ⚠️ for a reason: color detection requires FACE/CORNER-domain vertex colors. That means the colors must live per-corner (per-face), not per-vertex (POINT domain) - because POINT-domain colors are shared at vertices, so two faces meeting at a vertex report the same color and there's nothing to detect. To feed this node correctly, sample colors with BD_SampleVoxelgridColors in face mode (which produces the CORNER domain). Get this wrong and FROM_COLORS silently finds nothing.

Outputs: the marked mesh, an edge_preview TRIMESH, edge_metadata (an EDGE_METADATA object you can feed to BD Blender Merge Planes or BD Combine Edge Metadata), and status.

Install

Pack install as usual:

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

(ComfyUI Manager → "BrainDead", restart.) It's a Blender node, so the recurring rule applies: a real Blender must be on the system (/usr/bin/blender, a sibling pack, or a bundled build you place yourself) - the README's "bundled" claim refers to scripts, not the binary. Keep ComfyUI current for the V3 API.

The typical pipeline shape: BD Planar Grouping (clean boundaries) → BD Blender Edge Marking (FROM_COLORS_AND_ANGLE) → BD Blender Merge Planes (delimit_sharp=True) - that's the pack's documented hard-edge preservation chain, and each node in it depends on the one before doing its job.