QuadFix Lite is a free, open-source add-on for Blender 4.2 LTS, 4.5 LTS and 5.x. It turns triangles and curved n-gons into quads, cleans up meshes after Boolean cuts and imports (STL, OBJ, FBX, CAD, 3D scans, AI-generated meshes) and shows you exactly which faces are still not quads. Three buttons, no settings to learn, works on a selection or on the whole mesh.
Download the latest release | Blender 4.2+ | GPL-3.0-or-later | pure Python, no dependencies (tested on macOS; should work on Windows and Linux, reports welcome)
Get the full version: QuadFix on Superhive or Gumroad adds Fill Holes with Quads (closes holes with a proper quad grid, no triangle fans). Lite stays free and complete for everything listed below.
Triangulated scan-like mesh: before (all red = non-quads) and after N-gons to Quads. Red faces in the result are the ones that are still not quads.
| Button | What it does |
|---|---|
| N-gons to Quads | Triangulates curved n-gons and joins triangles into quads. Flat n-gons (caps, CAD faces) are left alone by default, so clean flat surfaces stay clean. |
| Clean & Quad | One click after a Boolean or an import: merge doubles, remove degenerate and loose geometry, limited dissolve (keeps sharp edges and seams), tris to quads, recalculate normals. |
| Select Non-Quads & Holes | Selects every triangle and n-gon and every open boundary edge, and prints the counts in the panel, so you see what is left to fix. |
Boolean cut result before and after Clean & Quad.
- Download
quadfix_lite-1.0.0.zipfrom the Releases page. Do not unzip it. - In Blender open Edit > Preferences > Get Extensions, click the small arrow menu at the top right and choose Install from Disk, then pick the zip.
- In the 3D viewport press
Tab(Edit Mode), pressNand open the QuadFix Lite tab.
- Select a mesh,
Tabinto Edit Mode, open the QuadFix Lite tab in the sidebar (N). - Press Select Non-Quads & Holes to see what needs work.
- Select the faces you want to fix (or press
A) and press N-gons to Quads or Clean & Quad. - Read the before/after counts at the bottom of the panel.
Ctrl+Z(Cmd+Zon Mac) undoes any step in one go.
Untick Only Selected to process the whole mesh.
- After a Boolean cut leaves triangles, n-gons and loose bits around the cut.
- STL, OBJ, FBX and CAD imports (STEP, IGES exported as meshes) full of triangles and duplicate vertices.
- 3D scans and photogrammetry meshes where you want fewer triangles before sculpting or UV work.
- AI-generated meshes (Meshy, Tripo, Hunyuan3D and similar) that come in as triangle soup.
- Game assets that must be quads before UV unwrapping, subdivision or baking.
- 3D printing prep: Select Non-Quads & Holes shows open boundary edges (holes) before you export an STL.
Blender's Face > Tris to Quads only joins pairs of neighbouring triangles, and only if their normals and the resulting shape are within Max Face Angle and Max Shape Angle. Options such as Compare Seams / Sharp / UVs / Materials block joins across those borders. It also does nothing with n-gons. QuadFix Lite triangulates curved n-gons first, then joins triangles with adjustable angles, and Aggressive Quads joins any two triangles regardless of angle when you want the fewest triangles.
Select the n-gons, triangulate them (Ctrl+T) and run Tris to Quads (Alt+J). QuadFix Lite does both in one click and skips flat n-gons on purpose. Flat n-gons are harmless unless you plan to subdivide or deform the mesh.
Merge by Distance, Limited Dissolve with a few degrees of angle, then Tris to Quads and recalculate normals. Clean & Quad runs that sequence, keeps sharp edges and seams, and reports vertex, quad, triangle and n-gon counts before and after.
Select > Select All by Trait > Faces by Sides finds faces with more than 4 vertices. Select Non-Quads & Holes finds all triangles and n-gons and the open boundary edges in one click.
No. QuadFix Lite does not fill holes: closing a hole with a proper quad grid is a separate, harder problem. That is what the full QuadFix add-on (paid, on Superhive and Gumroad) does. Lite stays free and complete for what it lists here.
No. It repairs the mesh you have and does not rebuild edge flow. On dense scans some triangles will remain. For automatic retopology use a remesher such as Quad Remesher, QRemeshify or Blender's own Quadriflow.
Yes. The test suite (38 checks on Boolean, scan, AI-like and attributed meshes, with vertex, edge and face select modes, partial selections and undo) passes on Blender 4.2.23, 4.5.14 and 5.2.2. The suite also checks that UV maps, vertex groups and colour attributes are still there afterwards.
No. Pure Python with Blender's own bmesh, no internet access, no dependencies.
| Option | Default | Meaning |
|---|---|---|
| Only Selected | on | Restrict to the selection (off = whole mesh) |
| Face Angle | 90 deg | Max angle between two triangle normals to join them |
| Shape Angle | 90 deg | Max deviation from a rectangle to accept a quad |
| Keep Planar N-gons | on | Leave flat n-gons untouched, convert only curved ones and triangles |
| Aggressive Quads | off | Join any two triangles into a quad, fewest triangles, less regular shapes |
| Merge Distance | 0.0001 | Merge vertices closer than this (Clean & Quad) |
| Dissolve Angle | 5 deg | Limited dissolve angle (Clean & Quad) |
| Keep Sharp Edges | on | Do not dissolve edges marked sharp or seam |
- Not a remesher and not an automatic retopology tool.
- Does not fill holes (see the full version above).
- Very irregular meshes and dense scans keep some triangles. Try Aggressive Quads if you prefer fewer triangles over regular shapes.
tests/run_all_versions.sh runs the assertion suite on every Blender found in /Applications and ~/Applications/blender-versions. Bug reports and pull requests are welcome, please attach a small .blend that shows the problem.
GPL-3.0-or-later, see LICENSE. Blender add-ons that use the Blender Python API must be GPL-compatible, and the Blender Extensions platform requires GPL-3.0-or-later for add-ons.
Keywords: Blender add-on, Blender extension, tris to quads, n-gons to quads, convert triangles to quads, clean up mesh after boolean, select non-quads, mesh cleanup, STL import cleanup, 3D scan cleanup, AI generated mesh cleanup, Meshy, Tripo, Hunyuan3D.