MeshRepair Documentation

3D Mesh Repair

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MeshRepair for Blender - User Guide

Blender addon for mesh hole detection and filling

MeshRepair for Blender integrates the MeshRepair engine directly into Blender’s interface, providing access to hole detection and filling operations from the sidebar panel. This guide covers installation, configuration, and usage.

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Table of Contents

• Feature Summary
• Installation
• Interface Overview
• Preset Operations
• Manual Operations
• Edit Mode Operations
• Preprocessing Options
• Hole Filling Options
• Results and Statistics
• General Guidelines
• Troubleshooting

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Feature Summary

Feature	Description
Preset Modes	C⁰, C¹, C² continuity presets
Edit Mode Support	Process selected faces only
Preprocessing	Topology cleanup before hole filling
Statistics Display	Operation results and timing
Undo Support	Full integration with Blender’s undo system
Multi-threaded	Parallel processing via external engine

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Installation

Step 1: Install the Engine

The addon requires the MeshRepair engine executable:

1. Download from Patreon or build from source
2. Extract to a permanent location:
   • Windows: C:\Program Files\MeshRepair\
   • Linux: /usr/local/bin/ or ~/meshrepair/
   • macOS: /Applications/MeshRepair/ or /usr/local/bin/

Step 2: Install the Addon

1. Download meshrepair_blender.zip from releases
2. In Blender: Edit → Preferences → Add-ons
3. Click Install… and select the ZIP file
4. Enable “Mesh: MeshRepair”

Step 3: Configure Engine Path

1. In addon preferences, click Detect Engine for automatic detection
2. If detection fails, manually browse to the meshrepair executable
3. Click Test Engine to verify connectivity

Verification

The Engine Status panel should display:

• Status: Ready (green indicator)
• Engine version number

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Interface Overview

Panel Location

1. Select a mesh object
2. Press N to open the sidebar
3. Select the Mesh Repair tab

Panel Structure

Section	Function
Engine Status	Connection status and version (collapsible)
Context Info	Current mode and mesh/selection data
Operation Buttons	Preset or manual operation controls
Preprocessing Options	Topology cleanup settings (collapsible)
Hole Filling Options	Algorithm parameters (collapsible)
Results	Statistics from last operation

Context Display

The panel displays context information based on current mode:

Mode	Information Displayed
Object Mode	Object name, total face count
Edit Mode	Selected faces / total faces, scope selector
No Selection	Warning message

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Preset Operations

For standard use cases, preset buttons provide configured parameter combinations:

C⁰ (Fast)

Parameter	Value
Continuity	C⁰ (positional)
Refinement	Disabled
Cubic Search	Skipped

Suitable for: Preview, large meshes, non-critical repairs

C¹ (Standard)

Parameter	Value
Continuity	C¹ (tangent)
Refinement	Enabled
Cubic Search	Normal

Suitable for: General use, balanced quality and performance

C² (High Quality)

Parameter	Value
Continuity	C² (curvature)
Refinement	Enabled
Cubic Search	Normal

Suitable for: Final output, additive manufacturing, high-fidelity requirements

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Manual Operations

For fine control, switch to Custom mode:

Operation Sequence

1. Preprocess Mesh

Executes topology cleanup operations.

Operations performed:

• Duplicate vertex merging
• Non-manifold geometry removal
• 3-face fan collapse
• Isolated vertex removal

2. Detect Holes

Analyzes mesh and reports hole count.

Output:

• Total holes detected
• Hole size distribution

3. Fill Holes

Fills detected holes using configured parameters.

Output:

• Holes filled successfully
• Holes failed
• Holes skipped (exceeded size limits)
• Geometry added (vertices, faces)

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Edit Mode Operations

The addon supports processing selected regions in Edit Mode.

Use Cases

Scenario	Benefit
Selective repair	Process specific areas only
Preserve intentional openings	Skip holes that should remain open
Large mesh processing	Reduce computation by limiting scope
Iterative workflow	Address problems incrementally

Scope Selection

In Edit Mode, the Scope option controls processing extent:

Option	Behavior
Remesh	Treat selected faces as a hole rim, delete them, and fill the opening
Selection	Keep selected faces, fill holes found inside the selection
Whole Mesh	Process entire mesh regardless of selection

Remesh:

Selection:

Selection Workflow

1. Enter Edit Mode (Tab)
2. Switch to Face Select mode (3)
3. Select faces surrounding holes to repair
4. Include adequate surrounding geometry for blending
5. Execute repair operation

Warning:

• Selection mode is quite brittle; ensure proper selection to avoid unintended results.
• Make sure to use polygon selection, not vertex or edge selection.
• Sometimes expanding the selection Ctrl+ couple times and shrinking Ctrl- it back helps to get a clean selection.
• Delete new geometry if results are unsatisfactory and run in Whole Mesh mode or in Object Mode.

Selection Expansion

The addon automatically expands selection to include neighboring geometry for smooth blending. Control this with Expand (0 = Auto):

Value	Behavior
0 (Auto)	Automatically chooses expansion based on continuity (at least 1 ring, 2 rings for C²)
1-8	Manual expansion iterations

Default is auto. Higher values provide smoother blending at increased computation cost.

Selection Boundary Handling

The addon distinguishes between:

• Selection boundaries: Edges of the selected region (not holes)
• Actual holes: Gaps in the mesh surface

Selection boundaries are automatically excluded from hole filling.

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Preprocessing Options

The Preprocessing panel is open by default; use it to access cleanup settings:

Presets

Preset	Description
Light	Duplicates and isolated vertices only
Full	All cleanup operations enabled

Individual Operations

Option	Description	Default
Remove Duplicates	Merge coincident vertices	Enabled
Remove Non-Manifold	Remove invalid topology	Enabled
Remove 3-Face Fans	Collapse degenerate configurations	Enabled
Remove Isolated	Delete unconnected vertices	Enabled
Keep Largest Only	Remove small disconnected components	Disabled
Remove Long Edges	Remove polygons containing edges above a length ratio threshold	Disabled

Advanced Parameters

Parameter	Default	Range	Description
Non-Manifold Depth	10	1-20	Search recursion limit
Duplicate Threshold	0.0001	0.0-1.0	Distance for coincidence detection
Max Edge Ratio	0.125	0.0-10.0	When Remove Long Edges is enabled, edges longer than this fraction of the object bounding-box diagonal mark their polygons for removal

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Hole Filling Options

The Hole Filling panel is open by default; use it to access algorithm parameters:

Size Limits

Parameter	Default	Description
Max Boundary	1000	Maximum hole boundary vertices
Max Diameter	0.1	Maximum diameter as ratio of mesh bbox

Holes exceeding these limits are skipped. The diameter check uses the full object bounding-box diagonal cached before partitioning, so threaded fills and edit-mode scopes use the same reference. For very large openings, increase Max Diameter above 1.0.

Quality Parameters

Parameter	Options	Description
Continuity	C⁰, C¹, C²	Surface smoothness level
Refine Mesh	On/Off	Match local triangle density

Continuity Levels

Level	Description	Computation
C⁰	Positional continuity	Low
C¹	Tangent continuity	Medium
C²	Curvature continuity	High

Algorithm Parameters

Parameter	Default	Description
Use 2D Triangulation	Enabled	Primary triangulation method
Use 3D Delaunay	Enabled	Fallback triangulation
Skip Cubic Search	Disabled	Skip exhaustive algorithm
Partitioned Parallel	Enabled	Multi-threaded processing

Default values are suitable for most cases.

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Results and Statistics

After operations, the Results & Statistics panel (between Engine Status and Main Operations) displays statistics:

Summary

Field	Description
Operation	Type of operation performed
Status	Success or error indication
Time	Execution duration

Preprocessing Statistics

Statistic	Description
Duplicates	Vertices merged
Non-manifold	Invalid geometry removed
Long-edge Polygons	Polygons removed due to edges exceeding the configured max edge ratio
3-Face Fans	Configurations collapsed
Isolated	Unconnected vertices removed

Hole Filling Statistics

Statistic	Description
Detected	Total holes found
Filled	Successfully repaired
Failed	Unable to repair
Skipped	Exceeded size limits
Vertices Added	New vertices created
Faces Added	New triangles created

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General Guidelines

Recommendation	Rationale
Save before repair	Undo support exists, but saves provide fallback
Start with presets	Adjust parameters only if results are unsatisfactory
Use Edit Mode for large meshes	Reduces computation by limiting scope
Check statistics	Non-zero failed count indicates potential issues

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Troubleshooting

Engine Not Found

Resolution:

1. Open addon preferences
2. Click Detect Engine or browse manually
3. On Linux/macOS: verify executable permissions (chmod +x meshrepair)

No Holes Detected

Possible causes:

• Mesh is watertight
• All holes exceed size limits
• Preprocessing required

Resolution:

1. Run preprocessing first
2. Increase Max Boundary and Max Diameter values
3. Inspect mesh in Edit Mode (Select All, check for boundaries)

Filling Failures

Possible causes:

• Degenerate geometry
• Self-intersecting hole boundaries
• Complex non-planar holes

Resolution:

1. Disable “Use 2D Triangulation”
2. Run full preprocessing
3. Repair problematic areas manually in Edit Mode

Performance Issues

Resolution:

1. Use C⁰ preset for initial testing
2. Process large meshes in sections using Edit Mode
3. Reduce Max Boundary to skip large holes
4. Verify thread count in addon preferences

Unexpected Results

Resolution:

1. Undo (Ctrl+Z) and adjust parameters
2. Use Edit Mode for section-by-section repair
3. Run preprocessing before filling
4. Check for overlapping or self-intersecting geometry

Debug Information

For issue reporting, enable verbose output:

1. Open addon preferences
2. Set Verbosity to 3 (Debug) or 4 (Trace)
3. Open system console:
   • Windows: Window → Toggle System Console
   • Linux/macOS: Launch Blender from terminal
4. Execute operation and capture console output

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Addon Preferences Reference

Access via Edit → Preferences → Add-ons → Mesh: MeshRepair

Engine Settings

Setting	Description
Engine Path	Path to meshrepair executable
Detect Engine	Automatic path detection
Test Engine	Verify engine connectivity

Performance

Setting	Default	Description
Thread Count	8	Worker threads (0 = automatic)

Debugging

Setting	Default	Description
Verbosity	1 (Info)	Output detail level (0-4)
Temp Directory	Empty	Debug file output location
Socket Mode	Disabled	TCP connection (for debugging)

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Related Documentation

• CLI Guide - Command-line interface usage
• Index - Project overview

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References

Hole filling algorithm:

Peter Liepa. “Filling Holes in Meshes.” Eurographics Symposium on Geometry Processing, 2003.

Fairing algorithm:

Mario Botsch et al. “On Linear Variational Surface Deformation Methods.” IEEE Transactions on Visualization and Computer Graphics, 2008.