[vtkusers] Mesh cutting using freehand curve

[Goodwin Lawlor]

Hi Miguel,

Try out this pipeline:
(in Tcl but it's the same idea in any language)

  vtkPoints selectionPoints
    selectionPoints InsertNextPoint 1.0 1.0 1.0
# etc...

  vtkSelectPolyData select
    select SetLoop selectionPoints
# connect your data here
    select SetInputConnection [mydataFilter GetOutputPort]
    select GenerateSelectionScalarsOn
    select SetSelectionModeToLargestRegion;

  vtkClipPolyData selectclip
    selectclip SetInputConnection [select GetOutputPort]
    selectclip SetValue 0.0

It's not 100% robust but works for most meshes that have well behaved
topology...

hth

Goodwin

On Tue, May 22, 2012 at 4:45 AM, Miguel Sotaquira <msotaquira at gmail.com>wrote:

> Hi everyone!
>
> I have a 3D manifold mesh and I want to be able to cut it using a freehand
> (drawn by user) contour. An example of such a mesh and the contour drawn by
> the user is shown in this image: http://postimage.org/image/sbnmcoodj/. By
> cutting I mean generating a 3D surface from the freehand contour and then
> splitting the mesh in two parts.
>
> Up to this point I've came up with this workflow for generating the
> freehand contour: vtkContourWidget -> vtkPolygonalSurfacePointPlacer. With
> this approach I'm able to draw the contour on the polydata mesh (see
> previous figure) and extract the set of contour point coordinates.
>
> However I'm lost from this point:
> - How to generate the 3D cutting surface?
> - Which would be the most adequate class to perform the cutting:
> vtkClipPolyData, vtkCutter, vtkExtractPolyDataGeometry?
> - In any of the previous classes I need a vtkImplicitFunction. How to
> define a vtkImplicitFunction using the 3D cutting surface?
>
> Thanks for any suggestions,
> Miguel
>
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