Manifold Evolved is a Blender 4.2+ extension for repairing meshes intended for

3D printing. It combines a detail-preserving topology repair loop with an

optional voxel reconstruction fallback for damage that local mesh edits cannot

resolve reliably.

## Why it is different from 3D Print Toolbox

Blender's bundled Make Manifold repeatedly fills holes and deletes newly

non-manifold vertices, then uses only vertex/edge/face counts to decide whether

it is stuck. Manifold Evolved instead:

- measures boundary, wire, multi-face, misoriented, degenerate, duplicate, and

bow-tie defects after every pass;

- merges close vertices, removes loose and degenerate geometry, deletes strict

interior partitions, performs Limited Dissolve, fills boundary loops, and

retries Blender's contextual Fill for difficult closed loops;

- separates disconnected face fans at bow-tie vertices without tearing their

surrounding edges;

- splits edges shared by three or more faces and closes the resulting surface

boundaries;

- keeps a pass only when the measured topology improves, so an unsuccessful

local attempt is rolled back;

- detects non-adjacent triangle intersections after topology repair;

- can escalate to Blender's OpenVDB-backed voxel remesher when a mesh remains

intersecting or otherwise irreparable with local edits.

## Repair modes

- Auto Repair: runs the detail-preserving pass first. It uses voxel rebuild

only when topology defects or self-intersections remain.

- Keep Detail: never voxelizes. Use this when exact surface placement, UVs,

or existing topology matter most. Any remaining defects are reported.

- Voxel Rebuild: immediately reconstructs a watertight volume. This is the

most reliable choice for heavily overlapping sculpts, Boolean debris, scans,

and slicer-bound models where printable geometry matters more than topology.

The panel also includes Analyze and Select Issues. Analyze reports actual

defect categories and self-intersections; Select Issues enters Edit Mode and

selects the local topology errors that remain.

## Install

1. Install manifold_evolved-0.1.0.zip using **Edit > Preferences > Extensions

> Install from Disk**.

2. Open the 3D Viewport sidebar with N.

3. Choose the 3D Print tab, then open Manifold Evolved.

## Suggested workflow

1. Duplicate an important model or save the .blend; Blender Undo is supported.

2. Select the active mesh and click Auto Repair.

3. Inspect the result summary. A green Print manifold result means the mesh is

closed, consistently oriented, free of local non-manifold topology, and has

no detected non-adjacent triangle intersections.

4. If fine features are too soft, Undo, open Advanced, and increase **Voxel

Resolution** (or use a smaller custom voxel size). Alternatively use **Keep

Detail** and repair any selected residual intersections manually.

## Important limits

- Voxel rebuild intentionally replaces topology and loses mesh data layers such

as UVs. It operates on base mesh data and does not apply the modifier stack.

- Objects with shape keys are skipped because topology-changing repair would

invalidate their key data.

- Merge distance and voxel size operate in local mesh units. Apply non-uniform

object scale first when exact physical tolerances matter.

- No automatic repair can infer the intended solid for a completely open sheet

or decide whether every enclosed cavity is intentional. Auto Repair retains a

local result when it improves, and reports a failure if voxel reconstruction

cannot find a volume.

## Verification

The integration suite creates deliberately broken meshes inside Blender and

checks open holes, flipped faces, unwelded STL-style face soup, bow-tie vertices,

multi-face junctions, intersecting solids, rollback behavior, and Edit Mode

restoration. It is exercised against Blender 5.0 and 5.1 during development.

Run it from the repository root with:

```powershell

& "C:\Program Files\Blender Foundation\Blender 5.1\blender.exe" `

--background --factory-startup --python ".\tests\blender_integration.py"

```

License: GPL-3.0-or-later.