[vtkusers] vtkImagePlaneWidget: how to update plane's orientation?

[Miguel Sotaquirá]

Hi again,

So I've managed to rotate the plane widget 90 degrees (see code below) but
somehow the rotated plane is not located on the center of the 3D volume. In
the code below I define the origin of the plane widget (wc) as the center
of the volume in x,y,z coordinates. I don't know if I'm not defining
correctly this center or the transformation (or both?)

How can I ensure that the center of the plane matches the center of the
volume?

Thanks,
Miguel

// Get volume's center
vtkSmartPointer<vtkImageData> imageData
= this->planeWidget[whichPlane]->GetResliceOutput();
double spacing[3];
imageData->GetSpacing(spacing);
double origin[3];
imageData->GetOrigin(origin);
int extent[6];
imageData->GetWholeExtent(extent);
 // Define widget's center as the center of the volume
double wc[3];
wc[0] = origin[0] + 0.5 * spacing[0] * ( extent[0] + extent[1] );
wc[1] = origin[1] + 0.5 * spacing[1] * ( extent[2] + extent[3] );
wc[2] = origin[2] + 0.5 * spacing[2] * ( extent[4] + extent[5] );
 // planeWidget's vector 2 (used as the axis of rotation)
double v2[3];
this->planeWidget[whichPlane]->GetVector2(v2);
// Transform
vtkSmartPointer<vtkTransform> transform
= vtkSmartPointer<vtkTransform>::New();
transform->PreMultiply();
transform->Translate(wc[0],wc[1],wc[2]);
transform->RotateWXYZ(90,v2[0],v2[1],v2[2]);
transform->Translate(-wc[0],-wc[1],-wc[2]);
// Modify and update planeWidget
double newpt[3];
transform->TransformPoint(this->planeWidget[whichPlane]->GetPoint1(),newpt);
this->planeWidget[whichPlane]->SetPoint1(newpt);
transform->TransformPoint(this->planeWidget[whichPlane]->GetPoint2(),newpt);
this->planeWidget[whichPlane]->SetPoint2(newpt);
transform->TransformPoint(this->planeWidget[whichPlane]->GetOrigin(),newpt);
this->planeWidget[whichPlane]->SetOrigin(newpt);
planeWidget[whichPlane]->UpdatePlacement();



2012/3/23 Miguel Sotaquirá <msotaquira at gmail.com>

> Hi everybody!
>
> I've implemented a four pane viewer using the example found
> at Examples/GUI/Qt/FourPaneViewer/QtVTKRenderWindows.cxx. This viewer
> allows me to explore a 3-D volume using a set of three vtkImagePlaneWidgets
> that can be interactively placed (translated, rotated) by the user using
> mouse events.
>
> What I want to do now after user interaction is to take one of these
> planes and rotate it 90 degrees along its normal, and update the four panes
> accordingly. In order to do so I'm using this workflow:
>
> - Define a vtkTransform (transform) and SetMatrix as vtkImagePlaneWidget's
> current orientation:
>     vtkSmartPointer<vtkTransform> transform
> = vtkSmartPointer<vtkTransform>::New();
>     transform->PreMultiply();
>     transform->SetMatrix(planeWidget->GetResliceAxes());
>
> - Apply 90 degrees rotation around Y axis:
>     transform->RotateY(90);
>
> - Update planeWidget using methods SetOrigin, SetPoint1, SetPoint2 and
> UpdatePlacement, where origin, point1, point2 are extracted from "transform"
>
> When using this approach I get strange results: neither planeWidget's
> origin nor its extension are well defined, and I'm not able to update the
> four panes accordingly. The origin is located outside the 3-D volume, and
> the extension does not cover the entire volume.
>
> Am I missing something? How to correctly update planeWidget's orientation?
> Thanks for your help,
>
> Miguel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20120323/6ce13af8/attachment.htm>