vtkSplineRepresentation and/or vtkSplineWidget control visibility and other properties of control handles

Development
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Hi All,

I was wondering if there was a way in Python interface of VTK for individually control the properties of the props/actors (handles, line) that vtkSplineRepresentation or vtkSplineWidget produce? I see methods that allow access to individual props are protected. Also, the handle properties are shared between all the handles. I am guessing there isnt a way to do this in Python, but I wonder if I missed something that others can chime in on?

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VTK 3D widgets are very limited and do not have a comprehensive API, probably because very few applications use them. If you miss some specific APIs then you can add them in C++ and probably VTK developers will accept your merge request.

However, if you don’t want to do this and/or you need more sophisticated VTK widgets then you can use one of the free, open-source VTK-based applications that offer Python interface (3D Slicer, Paraview, etc.).

I am one of the developers of 3D Slicer, so I can comment on what is available in the curve widget there:

  • show and edit curve in multiple views; both 2D slice and 3D views
  • open and closed curve, with various interpolation types - linear, bspline, polynomial curve fit, etc.
  • constrain to surface, project to surface, path search on surface (shortest path or using custom weights computed from point scalars)
  • resample curve
  • smooth coordinate frame along the curve, with customizable initial curve normal direction
  • independently show/hide, lock, toggle color of each control point, label each control point
  • curve measurements: length, curvature, torsion, surface area for closed curves (even non-planar), custom measurements, coloring by measurement, etc.
  • lots of visualization and interaction options

These features are all available in Python, using VTK-based classes, in 3D Slicer application’s Python environment. Thanks to Kitware EU’s recent work, you can also import SlicerLib into your Python environment, or use it in the web browser via trame.

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Hi Andras,

Thanks for your input. Love Slicer3D and been using it for many years. I feared extending the base class is the only way if I want to do it in pure VTK python. An alternate approach is to use a set vtkSphereWidget as the control handle and connect the positional information to the spline representation via callback/signal/slots mechanism.

I am intrigued by the python slicer module you mentioned. Is this package published. I wasnt able to find it when I tried looking it up.

Thanks again! :slight_smile:

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SlicerTrame to make Slicer available in the web browser: GitHub - KitwareMedical/trame-slicer: Bring the capabilities of 3D Slicer to the web with modern UI using the trame framework!

Standalone SlicerLib Python package is discussed here: Trame-Slicer and SlicerLib wheel - Support - 3D Slicer Community