BT-Material/Submesh Painter Pro: Advanced Material & Submesh Painting System

Streamline Your Editor Workflow with Direct Material & Submesh Assignment

Skip the tedious back-and-forth between Unity and external 3D software (like Blender or Maya) just to assign a new material to a specific part of your model. BT-Material Painter Pro is a practical, performance-friendly editor tool that lets you paint selections on your meshes and automatically split them into proper submeshes right inside Unity.

Perfect for prototyping, hyper-casual development, or making quick material adjustments to existing props and characters without leaving the editor.

🎨 Core Painting & Mesh Systems

Spatial Hash Brush - Smooth Editor Performance

• Responsive Interaction: Uses a custom spatial grid (MeshSpatialHash) to ensure smooth triangle selection without lagging the Editor, even on higher-poly meshes.
• Dynamic Brush Control: Quickly resize your brush radius in the Scene View using Shift+Scroll.
• Precision Mode: Drop the radius to zero for pixel-perfect, single-triangle selections.
• Paint & Erase: Fluidly toggle between adding and removing triangles with the Shift key.

Smart Topology Selection - Quick Geometry Handling

• Select Linked [L]: Isolate floating geometry islands (like glasses on a character or leaves on a tree) with a single keystroke.
• Grow [G] & Shrink [H]: Expand or contract your active selection by edge rings.
• Invert [I] & Clear [C]: Flip or clear your selections instantly for fast masking.
• Submesh Isolation: Automatically extract and select triangles from a model's existing material groups.

Dynamic Submesh Builder - Real Geometry Separation

• Physical Submeshes: This tool doesn't just paint vertex colors; it physically rebuilds your mesh into new submesh groups for true Material assignment.
• Skinned Mesh Support: Safely processes animated characters (SkinnedMeshRenderer). It separates materials while keeping your bone weights and rigging data completely intact.
• Draw Call Optimizer: The "Merge Same Materials" option automatically combines identical material slots into single submeshes, keeping your draw calls to a minimum.

Material Slot Manager - Rapid Prototyping

• Pipeline Auto-Detection: Automatically creates materials perfectly configured for your active pipeline (Standard, URP, or HDRP).
• 40 Quick Color Presets: Block out levels instantly with a built-in palette of ready-to-use color materials.
• Slot Management: Lock specific slots to protect complex borders while painting, or hide them to see underneath.
• Custom Materials: Easily drag and drop any of your existing Unity materials into the slots.

🚀 Editor Features & Workflow

Clean & Efficient UI

• Modern, scalable UI Toolkit interface with real-time triangle count monitoring.
• Scene view debugging with visual selection overlays (batches drawing to maintain Editor FPS).
• Built-in 30-step Undo/Redo stack specifically for the painter to protect your workflow without breaking Unity's main history.
• Quick Reassign button (↺) to instantly recall your last complex selection.

Safe Asset Management

• Non-Destructive: Generates completely new .asset files. Your original imported models are never overwritten.
• Automatic Saving: Routes and saves new materials and generated meshes directly to your designated project folders.
• OBJ Exporter: Includes a built-in .obj and .mtl exporter if you need to take your newly separated meshes back to Blender/Maya.

📊 Practical Benefits

• Saves Iteration Time: Fix missing material zones or colorize props in seconds.
• Optimized Results: Built by developers who care about performance. Unused triangles can be pruned, and identical materials are merged automatically.
• Scalable: Works reliably on everything from simple mobile props to complex desktop characters.

🛡️ Developer-Friendly & Transparent Built on the robust BT-MeshForge architecture:

• Clean, non-intrusive namespaces (BT.MaterialPainter & BT.MeshExtractor) to prevent conflicts with your project.
• Full C# source code included.
• Detailed, straightforward documentation.

What You Get

• Complete, well-commented C# source code.
• PDF/Markdown Documentation.
• Dedicated UI Toolkit Editor window & Scene View handler.
• Built-in preset palette & exporter tools.