InterpBlendShape

InterpBlendShape is a custom Maya deformer plugin that offers an alternative to Maya's built-in linear blend — blending targets using surface and bezier interpolation. It supports GPU parallel execution and works on both meshes and curves.

InterpBlendShapeEditor is the accompanying toolset: a custom editor for creating and managing targets, inbetweens, paint data, surface drivers, and target-shape editing. Mirror and flip operations are significantly faster than Maya's native equivalents. The UI is built on a Qt MVC framework with real-time Maya synchronization, full undo/redo support, thread-safe scene loading, and draggable target ordering.

For full details on the deformer node, see the InterpBlendShape documentation.

What Is Included

• interpBlendShape_ui.py Main Maya UI entry point.
• smoke_test_interpblendshape.py Lightweight Maya smoke test for the core happy-path workflow.
• widgets/ Reusable UI components, delegates, popup helpers, and styling.

Install

1. Copy the interpBlendShape folder into:

   C:\Users\<username>\Documents\maya\2024\scripts\
   

2. Set up the Python path by either:
   • Dragging install_interpBlendShape.py into the Maya viewport — it will install itself automatically, or
   • Copying userSetup.py manually into:

     C:\Users\<username>\Documents\maya\2024\scripts\
     

     If you already have a userSetup.py, append its contents to your existing file instead of replacing it.
3. Download the compiled plugin for your Maya version from the Releases page and copy it into:

   C:\Program Files\Autodesk\Maya2024\bin\plug-ins\
   

4. Copy AEinterpBlendShapeTemplate.mel into:

   C:\Program Files\Autodesk\Maya2024\scripts\AETemplates\
   

Restart Maya, then launch the UI from the Script Editor:

from interpBlendShape_ui import showUI
showUI()

Requirements

• Maya 2023+ with PySide2
• Python 3.x
• The compiled interpBlendShape plugin available to Maya

Features

Deformer

• Surface and bezier interpolation as an alternative to Maya's linear blend
• GPU parallel execution for fast deformation
• Works on meshes and curves

Editor

• Create and manage interpBlendShape deformers from a custom editor
• Real-time DG and UI sync through Maya API callbacks
• Thread-safe scene loading with Maya data collected on the main thread and tree-building moved to a background QThread
• Full undo/redo support with chunked undo for drag-release and batch operations
• Add targets and inbetweens directly from scene selection
• Paint and edit target weights
• Vertex weight editor with normalization and lock controls
• Copy, mirror, and flip target weights — significantly faster than Maya's native mirror/flip
• Drag-and-drop target reordering
• Scene state persistence for expanded state and saved node order
• Mirror or flip target geometry
• Surface association modes:
  • Closest Component
  • Closest Point
  • Closest UV (Global)
  • Closest UV (Shell Center)

Known Limits

• UV-based shape editing is mesh-only.
• UV-based shape editing uses the current UV set on the mesh.
• Closest UV (Global) mirrors across global U = 0.5.
• Closest UV (Shell Center) mirrors across each shell's local U center.
• Inbetween weights must stay strictly between 0.0 and 1.0.

Smoke Test

Run this inside Maya's Script Editor after the plugin and scripts are available:

from smoke_test_interpblendshape import run_smoke_test
result = run_smoke_test()
print(result)

The smoke test covers:

• opening the UI
• creating a deformer node
• adding a target
• adding an inbetween
• opening the shape edit options popup
• executing a mirror target operation

Release Checklist

• Verify the plugin loads in the target Maya version
• Run the smoke test in Maya
• Confirm icons resolve correctly from the packaged location
• Test one mesh target workflow and one curve target workflow
• Verify shape editing on at least one mirrored mesh asset

License

The Python UI scripts are open source under the MIT License.

The compiled interpBlendShape.mll plugin is included as a binary. Source code for the C++ plugin is not publicly available.

Version

Current Python package version: 1.0.0