Optimization

The Optimization panel provides tools for reducing your model's complexity and improving performance. It's a container with several sub-panels:

• Atlas Generation = combine textures into a single atlas
• Material Operations = combine materials, convert to PNG, join meshes, remove doubles
• Mesh & Bone Cleanup - merge bones and weights, delete unused bones/groups
• Mesh Tools - general mesh preparation (separate, normals, transforms, shape keys)

Table of Contents

• Atlas Generation
• Material Operations
• Mesh & Bone Cleanup
• Mesh Tools

---

Atlas Generation

The Atlas tab helps you combine multiple textures into a single texture atlas, reducing draw calls and improving avatar performance.

⚠ Material Combiner is being removed in Cats 5.2.4.0. The external Material Combiner (used for atlasing) is no longer maintained by its author, so we are replacing it with our own atlas tool built directly into Cats. Until then, the current integration still works as described below.

What is an Atlas?

A texture atlas combines multiple textures into one larger texture, which:

• Reduces draw calls significantly
• Improves avatar performance
• Helps meet platform texture limitations
• Simplifies material management

Requirements

The Atlas feature requires the Shotariya Material Combiner (SMC) extension to be installed.

Installation States

The Atlas tab will show different interfaces depending on SMC status:

When SMC is NOT installed:

• Shows installation instructions
• Provides direct download link
• Explains why SMC is needed

When SMC is disabled:

• Shows quick enable button
• No restart required
• Instant access after enabling

When SMC is outdated:

• Shows version compatibility information
• Provides link to compatible version

When SMC is properly installed:

• Full access to atlas creation tools
• Material combining options available

How to Use Material Combiner

1. Select your model's armature or meshes
2. Open the Atlas tab in the Optimization panel
3. Review the list of materials
4. Check/uncheck boxes to include/exclude materials
   • Use Select All/Deselect All for quick selection
5. Configure atlas settings:
   • Set atlas size (texture resolution)
   • Set size for materials without images (default: 32px)
6. Click 'Save atlas to...' and choose save location
7. Wait for the atlas to be created

Important Notes

📝 For PBR/Normal maps: Use Tuxedo Blender Plugin instead. Material Combiner in Cats is primarily for diffuse textures.

📝 Material Combiner (Atlas) is not developed by us. Please report any issues on their GitHub.

⚠ Version Compatibility: Our Material Combiner fork is for Blender 5.1+. If you're using Blender 5.0 or older, use the original Material Combiner instead.

⚠ Troubleshooting: If materials don't merge properly or textures are missing from the atlas, check the Material Combiner troubleshooting guide.

Benefits of Using Atlas

• Reduces draw calls from multiple materials to one
• Significant performance improvement
• Helps meet platform mesh/material limits
• Easier to manage single material vs. many

---

Material Operations

The Material Operations sub-panel offers tools for optimizing materials and meshes.

Material Operations

Combine Materials

Merges multiple materials into fewer materials:

• Reduces draw calls
• Improves performance
• Maintains texture assignments
• Preserves UV maps
• Ideal for objects sharing similar materials

How to use:

1. Select your model
2. Click Combine Materials
3. Materials with the same properties will be merged

Convert All to PNG

Converts all textures in your model to PNG format:

• Ensures maximum compatibility across platforms
• Maintains alpha channels
• Helps prevent texture issues in-game
• Standard format for VRChat

How to use:

1. Select your model
2. Click Convert All to PNG
3. All textures will be converted and saved

Mesh Operations

Join Meshes

Join All:

• Combines all meshes into one object
• Maintains material assignments
• Preserves vertex groups and weights
• Ideal for final optimization

Join Selected:

• Merges only chosen meshes
• Perfect for partial optimization
• Keeps other meshes separate
• Useful for selective optimization

How to use:

1. Select meshes (for Join Selected)
2. Click the appropriate join button
3. Meshes will be combined

Cleanup Tools

Remove Doubles

Eliminates duplicate vertices in your mesh:

• Adjustable threshold for precise control
• Reduces vertex count
• Fixes common mesh issues
• Improves performance

How to use:

1. Select your mesh
2. Set the merge distance threshold
3. Click Remove Doubles
4. Duplicate vertices within the threshold will be merged

When to Use Each Feature

• Combine Materials: When you have many materials with similar properties
• Convert to PNG: Before uploading to VRChat or other platforms
• Join Meshes: For final optimization before export
• Remove Doubles: When mesh has overlapping or duplicate vertices

⚠ Important: These operations are permanent. Always save your work before using these tools. Consider keeping a backup of your original files.

---

Mesh & Bone Cleanup

The Mesh & Bone Cleanup sub-panel (formerly "Bone Merging") provides advanced tools for optimizing your avatar's armature and reducing bone count.

Main Settings

Merge Options

Merge Mesh:

• Available when multiple meshes are present
• Combines meshes before bone operations
• Preserves weight assignments

Merge Bone:

• Controls which bones to merge
• Smart selection based on bone influence
• Preserves important bones automatically

Merge Ratio:

• Sets the merging threshold (0.0 to 1.0)
• Higher values merge more aggressively
• Lower values are more conservative
• Recommended: Start with 0.5 and adjust

Primary Actions

Refresh Root:

• Updates root bone references
• Fixes hierarchy issues
• Ensures proper bone relations
• Use after making changes to armature

Bone Merge:

• Executes the merging process
• Combines selected bones based on settings
• Redistributes weights intelligently
• Reduces overall bone count

Weight Management

Merge Weights

Merge All:

• Combines all weight groups
• Optimizes weight distribution
• Reduces overall weight count
• Good for final optimization

Merge to Active:

• Transfers weights to active object
• Ideal for specific mesh optimization
• Maintains weight influence
• Use for selective optimization

Additional Options

Keep Merged Bones:

• Retains merged bones as backup
• Allows for reverting changes
• Useful for testing results
• Disable for maximum optimization

Merge Visible Meshes Only:

• Processes only visible objects
• Helps with selective optimization
• Maintains hidden backups
• Good for iterative workflow

Cleanup Tools

Delete Operations

Remove Zero Weight Bones:

• Deletes bones with no weight influence
• Reduces armature complexity
• Improves performance
• Safe to use in most cases

Remove Constraints:

• Clears bone constraints
• Simplifies armature behavior
• Reduces computation needs
• Use if constraints aren't needed

Remove Zero Weight Groups:

• Cleans empty vertex groups
• Reduces file size
• Improves viewport performance
• Safe cleanup operation

Keep Twist Bones Option:

• Preserves important animation bones
• Maintains smooth deformations
• Prevents animation issues
• Enable for better animation quality

Keep Empty Parent Bones:

• Retains parent bones even without weights
• Maintains hierarchy integrity
• Prevents structural issues
• Enable for complex rigs

Skip Hidden Bones:

• Ignores hidden bones during cleanup
• Preserves specific rig setups
• Ensures hidden bones remain unaffected
• Use when you have helper bones

Extra Operations

Duplicate Bones:

• Creates copies of selected bones
• Useful for custom rigging
• Maintains original structure
• Advanced feature for custom rigs

Connect Bones:

• Creates visual connections between bones
• Improves armature readability
• Helps with animation setup
• Makes bone relationships clearer

Best Practices

1. Always start with a backup - Bone merging significantly modifies your armature
2. Test merge ratios - Try different values on a copy first
3. Check animations after merging - Ensure movements still work correctly
4. Use cleanup tools last - Do all modifications before cleanup
5. Keep twist bones - Unless you're absolutely sure you don't need them
6. Refresh root after changes - Keep bone hierarchy up to date

Workflow Example

1. Start with Merge Ratio at 0.5
2. Enable Keep Merged Bones for safety
3. Click Bone Merge
4. Check the result
5. If satisfactory, run Remove Zero Weight Bones
6. Then Remove Zero Weight Groups
7. Finally Remove Constraints if not needed

⚠ Warning: These operations significantly modify your armature structure. Always keep a backup of your original file before proceeding. Test on a copy first if you're unsure.

---

Mesh Tools

The Mesh Tools sub-panel holds general mesh preparation and cleanup: Separate By, Normals (recalculate/flip), Apply Transformations, and shape-key tools (remove unused / repair / optimize static). See the dedicated Mesh Tools page for details.

The digitigrade-leg and twist-bone generation tools used to live here too, they now have their own Bone Tools panel.

---

Optimization Workflow

Recommended Order

1. Material Tab:

   • Join meshes if needed
   • Remove doubles
   • Combine materials

2. Atlas Tab:

   • Create texture atlas
   • Reduce material count

3. Bone Merging Tab:

   • Merge bones
   • Clean up unused bones and weights

4. Final Check:

   • Test animations
   • Verify materials
   • Check vertex counts

Performance Tips

• Atlasing gives the biggest performance boost
• Bone merging helps with platform limits
• Material combining reduces draw calls
• Remove doubles reduces vertex count

---

Related Pages:

• Quick Access - Basic model operations
• Merge & Attach - Merging multiple models
• Mesh Tools / Bone Tools - Mesh prep and bone generation
• Troubleshooting - Common optimization issues

---

Last Updated: July 28, 2026 | Plugin Version: 5.2.3.0 | Blender: 5.1 & 5.2 (5.2 LTS recommended)