OpenSubdiv limitations

OpenSubdiv General limitations

OpenSubdiv does not support:
- Non-manifold meshes
  Maya automatically defaults to Maya Catmull-Clark for meshes that contain non-manifold components.
  
  When OpenSubdiv cannot be used, an error message appears in the Script Editor and the polyShape node, indicating that the Maya Catmull-Clark subdivision method is active.
  
  Note: Modeling operations can generate non-manifold components temporarily. When a non-manifold mesh becomes manifold, the warning messages disappear and the subdivision method automatically switches to OpenSubdiv.
Due to driver issues, OpenCL acceleration for OpenSubdiv Catmull-Clark Uniform subdivision method does not work properly on Mac OS X systems with a Quadro 4000 card. To disable acceleration, use the environment variable MAYA_OPENCL_IGNORE_DRIVER_VERSION = 1.

OpenSubdiv Catmull-Clark Adaptive does not support:
- Depth of field
- Use Default Material
- Depth peeling
- Plug-in shader implemented with MPxShaderOverride
OpenSubdiv Catmull-Clark Adaptive only supports OpenGL 4 and DirectX11 compatible graphics cards.
Maya automatically defaults to Maya Catmull-Clark when OpenGL 4 or DirectX11 are not supported.

OpenSubdiv Displacement preview is derived from OpenSubdiv Catmull-Clark Adaptive, and thus shares its limitations.

Additionally, OpenSubdiv Displacement preview does not support:
- File texture node parameters (Alpha gain, etc).
- Non-tangent space vector displacements (i.e. global space not supported).