SmartWeight — Smarter Skin Weights for Blender Riggers

Bone-proximity prediction with topology-aware diffusion. Detect and fix candy wrapper, volume loss, weight leak.

Why SmartWeight

Blender's built-in automatic weights are a starting point, not a result. Every rigger spends time chasing candy-wrapper deformation at joints, volume loss at shoulders, and weight leak across opposite arms. SmartWeight predicts cleaner weights up front and then detects and fixes six kinds of weight problems so you ship a riggable mesh instead of debugging it.

Features

Predict Weights

• Bone-proximity prediction with edge-diffusion smoothing
• Heat Diffusion and Hybrid methods — bone-axis falloff plus edge diffusion along the mesh (in this version the two run the same calculation)
• Distance-Based method — pure inverse-distance weighting
• Per-bone prediction for fine-grained control

Issue Detection

• Candy wrapper at parent / child joints
• Volume loss on deforming joints
• Weight leak across body regions
• Asymmetric L / R weights
• Vertices with no weights, and vertices with more influences than your limit
• Every threshold is derived from the size of your rig, so the same checks work on a 1.8 m character, a 20 m creature and a scene modelled in centimetres — and the panel shows the distance being used

Fix Tools

• Targeted fix operator for each issue type
• Mirror weights L↔R, matching vertices across X within a distance tolerance
• Smooth weights: Laplacian, Distance-Based or Heat Map
• Auto-normalize to top-N influences (default 4 for game rigs)
• Cleans old weights before writing — no parasitic groups left over

Compatibility

• Blender: 4.2 LTS and later, tested on 4.2.9 and 5.2.0
• OS: Windows / macOS / Linux
• Rigs: Rigify, Mixamo, Auto-Rig Pro, custom humanoids

What you get

• SmartWeight add-on (Python only, no DLL)
• README with full quick-start guide
• Free updates for v1.x
• Support through marketplace messaging

Install

Edit → Preferences → Add-ons → arrow button in the top right corner → Install from Disk → pick the downloaded archive → enable. Press N in the 3D Viewport → SmartWeight tab.

License

GPL-3.0. Standard for Blender add-ons.