MetaMeshmizer

MetaMeshmizer is a batch optimization tool for Unreal Engine that automatically reduces static mesh triangle counts and downsizes textures used in their materials, boosting performance and reducing memory usage with minimal visual impact.

Overview

MetaMeshmizer provides two main batch processing functions:

1. Batch Static Mesh LOD Reduction - Reduces triangle/vertex counts for static meshes
2. Batch Texture Resize - Downsizes textures referenced by static meshes

Installation

1. Copy the MetaMeshmizer plugin folder to your project's Plugins directory
2. Restart Unreal Engine or regenerate project files
3. Enable the plugin in Edit → Plugins → Meta → MetaMeshmizer

Usage

Accessing the Tools

MetaMeshmizer can be accessed in two ways:

Method 1: Main Menu

• Navigate to Tools → Static Mesh Tools in the Unreal Engine menu bar
• Select either:
• Batch Reduce Static Mesh LODs (Selected Folders)
• Batch Halve Referenced Textures

Method 2: Content Browser Context Menu

• Right-click on a folder in the Content Browser
• Select either:
• Meta Static Mesh Batch LODs Reducer
• Meta Static Mesh Batch Texture Reducer

Function 1: Batch Static Mesh LOD Reduction

This function reduces the triangle and vertex counts of static meshes in selected folders, creating optimized LODs (Level of Detail) for better performance.

Parameters

The reduction dialog provides the following options:

Reduce Percent (10-100)

• Type: Float (10.0 - 100.0)
• Default: 50.0
• Description: Reduction percentage - how much to reduce the mesh. A value of 75% means the mesh will be reduced by 75%, leaving 25% of the original triangles/vertices. For example, if a mesh starts with 1000 triangles and you set 75%, it will end with 250 triangles (1000 - 750 = 250). Lower values result in less reduction, higher values result in more aggressive reduction.

Auto Perform (Checkbox)

• Type: Boolean
• Default: false
• Description: When enabled, automatically determines optimal Nanite and LOD Group settings based on the mesh's triangle count and bounds radius. This option OVERRIDES the "Enable Nanite Support" checkbox and "LOD Group" dropdown settings - your manual selections for these will be ignored when Auto Perform is enabled.

Auto Perform Logic:
- Nanite Enablement:
- Enabled if post-reduction triangle count ≥ 50,000
- Enabled if post-reduction triangle count ≥ 10,000 AND bounds radius > 500 units
- Disabled otherwise

• LOD Group Selection:
• SmallProp: Bounds radius ≤ 500 units AND triangles ≤ 10,000
• LargeProp: Bounds radius ≤ 500 units AND triangles > 10,000, OR bounds radius 500-2000 units AND triangles < 100,000
• LevelArchitecture: Bounds radius > 2000 units OR bounds radius 500-2000 units AND triangles ≥ 100,000

Enable Nanite Support (Checkbox)

• Type: Boolean
• Default: true
• Description: Enables Nanite virtualized geometry support for the mesh. Nanite is ideal for high-poly meshes (10,000+ triangles) and provides automatic LOD management. When enabled, the LOD Group setting is ignored (Nanite doesn't use traditional LOD groups). Note: This setting is overridden when "Auto Perform" is enabled.

Nanite Keep Triangle % (0-100)

• Type: Float (0.0 - 100.0)
• Default: 50.0
• Description: Keep percentage - how many triangles to keep (NOT reduction percentage). This is different from "Reduce Percent" above. A value of 50% means 50% of triangles will be kept for Nanite's fallback representation. This affects the simplified mesh used when Nanite cannot render the full detail. Lower values reduce memory but may impact quality at extreme distances.

LOD Group (Dropdown)

• Type: String (Enumeration)
• Options: None, SmallProp, LargeProp, LevelArchitecture
• Default: None
• Description: Sets the LOD Group for the mesh, which determines automatic LOD generation behavior:
• None: Custom manual LOD setup with 6 progressive LODs (LOD0 at specified reduction %, each subsequent LOD at 50% of previous)
• SmallProp: Optimized for small objects (props, decorations)
• LargeProp: Optimized for large objects (vehicles, furniture)
• LevelArchitecture: Optimized for architectural elements (buildings, structures)

Notes:
- LOD Group is ignored when Nanite is enabled.
- This setting is overridden when "Auto Perform" is enabled.

Support Ray Tracing (Checkbox)

• Type: Boolean
• Default: false
• Description: Enables ray tracing support for the mesh. This allows the mesh to participate in ray-traced lighting and reflections, but increases build time and memory usage.

Distance Field Scale (0.25-1.0)

• Type: Float (0.25 - 1.0)
• Default: 0.5
• Description: Scale factor for distance field resolution. Distance fields are used for soft shadows and ambient occlusion. Lower values reduce memory usage but may impact shadow quality. This setting is applied to all LODs.

Allow CPU Access (Checkbox)

• Type: Boolean
• Default: false
• Description: Allows the mesh data to be accessed from CPU code. This is required for certain gameplay features (e.g., procedural mesh generation, physics queries) but increases memory usage.

Settings Dialog

How It Works

1. Select one or more folders in the Content Browser
2. Launch the tool from the menu or context menu
3. Configure reduction parameters in the settings dialog
4. Click OK to start processing
5. A progress window displays the operation status
6. Meshes are processed sequentially with a progress bar

LOD Generation Behavior

When Nanite is Enabled:
- Only LOD0 is created with the specified reduction percentage
- Nanite handles automatic detail management
- LOD Group is set to None (not applicable)

When Nanite is Disabled and LOD Group is "None":
- Creates 6 LODs with progressive reduction:
- LOD0: Reduced by specified percentage (e.g., 50% reduction = 50% of original remains)
- LOD1: 50% of LOD0 (further reduction from LOD0)
- LOD2: 50% of LOD1 (further reduction from LOD1)
- LOD3: 50% of LOD2 (further reduction from LOD2)
- LOD4: 50% of LOD3 (further reduction from LOD3)
- LOD5: 50% of LOD4 (further reduction from LOD4)

When LOD Group is Set (SmallProp/LargeProp/LevelArchitecture):
- Only LOD0 is modified with the specified reduction percentage
- The LOD Group system automatically manages the LOD chain
- Additional LODs are generated based on the group's settings

Note: When "Auto Perform" is enabled, both "Enable Nanite Support" and "LOD Group" settings are overridden by the automatic logic.

Function 2: Batch Texture Resize

This function finds all textures referenced by static meshes in selected folders and reduces their resolution, saving memory and improving performance.

Parameters

The texture reduction dialog provides the following option:

Reduce Percent (25-100)

• Type: Float (25.0 - 100.0)
• Default: 50.0
• Description: Reduction percentage - how much to reduce the texture resolution. A value of 75% means the texture will be reduced by 75%, leaving 25% of the original resolution. For example, if a texture starts at 2048×2048 and you set 75%, it will end at 512×512 (2048 × 0.25 = 512). The value is clamped between 25% and 100% to ensure reasonable quality.

Example:
- Original texture: 2048×2048 (4,194,304 pixels)
- 50% reduction: 1024×1024 (1,048,576 pixels) - texture reduced by 50%, leaving 50% resolution
- 75% reduction: 512×512 (262,144 pixels) - texture reduced by 75%, leaving 25% resolution

Settings Dialog

How It Works

1. Select one or more folders in the Content Browser
2. Launch the tool from the menu or context menu
3. Enter the reduction percentage (25-100)
4. Click OK to start processing
5. The tool:
   - Scans all static meshes in selected folders
   - Collects all textures referenced by mesh materials
   - Removes duplicates (same texture referenced multiple times)
   - Resizes each unique texture to the specified percentage
6. A progress window displays the operation status

Texture Collection

The tool automatically finds textures from:
- Material instances (texture parameters)
- Material interfaces (used textures)
- All material slots in static meshes

Supported Texture Formats

The tool supports all standard Unreal Engine texture formats and preserves:
- Original format (RGBA, RGB, etc.)
- Gamma space (sRGB, Linear)
- Texture compression settings

Progress Window

Both functions display a progress window showing:
- Selected folders
- Current operation status
- Number of assets found
- Processing progress for each asset
- Completion status

Best Practices

Static Mesh Reduction

1. Start Conservative: Begin with 30-50% reduction (leaving 70-50% of original) and adjust based on visual quality. Remember: higher reduction percentage = more aggressive reduction = fewer triangles remain.
2. Use Auto Perform: Enable Auto Perform for automatic optimization based on mesh characteristics. Note that this will override your manual Nanite and LOD Group settings.
3. Nanite for High-Poly: Enable Nanite for meshes with 10,000+ triangles (or let Auto Perform decide)
4. LOD Groups: Use appropriate LOD Groups for consistent optimization across similar assets (unless Auto Perform is enabled)
5. Test in Context: Always test reduced meshes in your actual game/level to verify visual quality

Texture Resizing

1. Check Quality: Preview textures after resizing to ensure acceptable quality
2. Consider Usage: More important textures (hero assets) may need less reduction (lower reduction percentage)
3. Understand Reduction: Remember that 75% reduction means only 25% of original resolution remains (e.g., 2048×2048 becomes 512×512)
4. Batch Process: Process textures in batches by folder to maintain organization
5. Backup First: Consider backing up textures before batch resizing

Technical Details

Requirements

• Unreal Engine 5.7 or later
• Editor build (not available in packaged builds)
• MeshReductionInterface module (included with Unreal Engine)

Dependencies

• Core
• CoreUObject
• Engine
• UnrealEd
• EditorSubsystem
• AssetRegistry
• ContentBrowser
• ToolMenus
• MeshUtilities
• MeshReductionInterface

Limitations

• Mesh reduction only works in editor builds
• Texture resizing modifies source textures (consider backups)
• Large batches may take significant time to process
• Some meshes may not reduce well if they're already optimized

Troubleshooting

No Meshes Found

• Ensure folders contain Static Mesh assets (.uasset files)
• Check that folders are properly selected in Content Browser
• Verify asset registry has indexed the selected paths

Reduction Not Applied

• Check that meshes are not read-only
• Ensure you have write permissions for the asset files
• Verify the mesh has valid geometry (not empty or corrupted)

Texture Resize Fails

• Ensure textures are not compressed in an unsupported format
• Check that textures have valid source data
• Verify texture is not locked or in use by another process