QuadDoctor — Gumroad Product Listing

Product Name

QuadDoctor — Select N-Gons → BFF → Clean Quads (Blender)

Price

Solo: $9

Thumbnail

Use nostromo-deep/topology/quad-doctor.svg on #070809. "QUADDOCTOR" in spectral cyan #2A8B9B.

Short Description (Gumroad summary field, 160 chars)

The cheapest cure for n-gons. Select your n-gons, run BFF (Boundary-First Flattening), get clean quads. Phase 20A junction-aware. Single-purpose tool, $9, lifetime updates.

Full Description

The pain

Your import from Maya / Plasticity / SketchUp arrived as a sea of n-gons. You don't need a full retopology pass; you need to surgically replace the n-gons with quads while leaving the rest of the mesh alone.

QuadDoctor is the surgical tool. Select the n-gons (or use "Select All N-Gons"), run BFF, get quads in the same place. The rest of the mesh is untouched.

What it does

1. Select n-gons (or use the "Auto-Select All N-Gons" button)
2. Run BFF — Boundary-First Flattening computes a conformal parameterization of the selected region
3. Extract isolines — the orthogonal grid lines in BFF parameter space ARE the ideal quad edge loops (the conformal-isolines theorem)
4. Snap the new quads to your existing edge boundary so the surrounding topology is unchanged
5. Phase 20A junction-aware — at the boundary where new quads meet existing topology, QuadDoctor routes through the same dispatch_atlas dispatcher as HolyGrail (Hermite for N ≤ 3, fusion cell for N ≥ 4)

What's under the hood

• BFF solver (Sawhney-Crane 2017) — the same engine as ConformalUV
• Isoline extractor — pulls grid lines from BFF parameter space, snaps to the n-gon boundary
• Phase 20A dispatcher — junction handling at the patch boundary (the same engine as HolyGrail / Seam Inspector)
• SmartWeld — bundled feature for the final boundary stitch (Hungarian optimal vertex merge)

The workflow

1. Open Edit Mode on the offending mesh
2. Open N-Panel → ZForge → QuadDoctor
3. Click "Auto-Select All N-Gons" (or manually select)
4. Adjust target edge length (defaults to inferred from surrounding quads)
5. Click "Cure"
6. Review the result — undo (Ctrl-Z) if you want to tweak parameters

Why $9

QuadDoctor is a single-purpose tool, not a full retopology suite. If you need full automation on hard-surface boolean output, you want HolyGrail Auto-Retopo ($79 / $149). If you have a sea of n-gons and want them gone surgically, you want QuadDoctor ($9).

The math substrate is the same — both use BFF + the Phase 20A dispatcher. QuadDoctor is the cheaper, more focused surface.

Requirements

• Blender 4.0+
• Python 3.10+ (ships with Blender)
• NumPy (ships with Blender)
• No additional dependencies

Changelog

v0.2.0 — 2026-05-24 (staged)

• Phase 20A junction-aware boundary handling
• Auto-select n-gons button
• Target-edge-length inference from surrounding quads

Tags

blender, addon, n-gons, quad, retopology, BFF, surgical, cheap

File

quaddoctor-v0.2.0.zip (Blender addon zip — depends on zforge-core)

Suggested cross-sell

• HolyGrail Auto-Retopo ($79 / $149) — if your whole mesh needs retopo, not just the n-gons
• TopoGuard (free) — flags the n-gons before they bite you
• ZForge Suite ($99) — every tool

Provenance

• Source: zforge_core/topology/ (BFF + isoline extractor)
• Phase 20A integration: zforge_core/topology/fusion_seam.py (dispatcher) + seam_executor.py
• Hub: Zforge/product_hub/PRODUCT_HUB.md §4 Tier 2