[vtkusers] Clipping Planes

[James Robinson]

John,

 

Many thanks for replying. I have tried EVERYTHING. I have even tried
reloading all the props into the renderer. I have checked the altered bounds
on everything from the vtkUnstructuredGrid to the vtkPoints* pNodalGeometry.
None of the bounds are altered after the change (which, I would imagine, is
why the resetting of the clip planes has no effect). My workaround is:

 

void CSampleView::ResetCameraClippingRange(BOOL ShowDisplacement)

{   

//          float    bounds[6]  ;

//  Renderer->ComputeVisiblePropBounds(bounds) ;

//          Renderer->ResetCameraClippingRange() ;

 

  // TODO: add construction code here

    vtkInteractorStyleSwitch* pStyle =
(vtkInteractorStyleSwitch*)Interactor->GetInteractorStyle() ;

    if (ShowDisplacement)

            { 

                        pStyle->AutoAdjustCameraClippingRangeOff() ;

                        vtkCamera* pCamera = Renderer->GetActiveCamera() ;

                        pCamera->SetClippingRange(0.001, 1000.) ; //
Arbitrary - this could be automated

            } else

            {

                        pStyle->AutoAdjustCameraClippingRangeOn() ;

            }

            

}

 

which I call every time the displacement view option is chosen. Note that it
was at this level that I tried to ResetCameraClippingRange (both with bounds
computed and not), but to no avail.

 

Any other suggestions welcomed.

 

Regards,

 

Jim

 

James C Robinson, PhD, Chartered Engineer,

*     42 Rivergrove,

         Glanmire,

         Co. Cork,

         Eire

'     +353 21 4822028

         +353 87 2393010

6      +353 21 4822028

*    j.robinson at kepler-systems.com 

  _____  

From: John Biddiscombe [mailto:jbiddiscombe at skippingmouse.co.uk] 
Sent: 11 August 2004 12:20
To: j.robinson at kepler-systems.com; Vtk Users
Subject: Re: [vtkusers] Clipping Planes

 

After calling AddDisplacement(...) you are calling resetCameralippingRage()
yes? If not. try it.

 

JB

----- Original Message ----- 

From: James Robinson <mailto:j.robinson at kepler-systems.com>  

To: Vtk Users <mailto:vtkusers at vtk.org>  

Sent: Wednesday, August 11, 2004 11:24 AM

Subject: [vtkusers] Clipping Planes

 

Dear All,

 

I am having trouble (again) with clipping planes. I am trying to create a
viewer to view results of an FE analysis. Part of the results are the
displacements at the nodes of the finite element mesh. I read in the FE mesh
into a vtkUnstructuredGrid with the displacements as a vector field. I then
create a displaced geometry by adding them to the vtkUnstructuredGrid
geometry as follows:

 

void CSampleDoc::AddDisplacement(float factor)

{   vtkFloatArray *pDisplacement =
(vtkFloatArray*)this->pUnstructuredGrid->GetPointData()->GetVectors() ;

 

            vtkPoints* pNodalGeometry = this->pUnstructuredGrid->GetPoints()
;

 

            if (pDisplacement==NULL)

            { AfxMessageBox("No displacement set") ;

              return ;

            }

 

 

            float newcoords[3] ;

            float* x ;

            float* delta ;

 

            for (int i = 0; i < pNodalGeometry->GetNumberOfPoints(); i++)

            {  

               x = pNodalGeometry->GetPoint(i) ;

       delta = pDisplacement->GetTuple(i) ;

               for (int j = 0; j < 3; j++)

       { newcoords[j] = x[j] + factor*delta[j] ;

               }

       pNodalGeometry->SetPoint(i,newcoords) ;

            }

    this->pUnstructuredGrid->Update() ;

    this->pGeometry->SetInput(pUnstructuredGrid) ;

    this->pMeshMapper->SetInput(pGeometry->GetOutput());

    this->pMeshMapper->Update() ;

    this->pMeshActor->SetMapper(this->pMeshMapper) ;

}

 

This works (with some other quirky behaviour which I have circumvented). But
a problem that I am having difficulty with is that the clipping planes
remain as if the geometry hadn't been altered. Thus, as I rotate the object
(in trackball camera mode) the displaced object disappears. I have checked
the bounds of the viewable objects (using
Renderer->ComputeVisiblePropBounds(bounds) ;) and they are unaltered - thus
all the AutoClipping is thrown out of whack. It may very well be that (a) I
am doing things that are not meant to be catered for in vtk or (b) there is
a better (preferably simpler) way of achieving this effect. 

 

All suggestions gratefully welcomed.

 

Jim

 

James C Robinson, PhD, Chartered Engineer,

*     42 Rivergrove,

         Glanmire,

         Co. Cork,

         Eire

'     +353 21 4822028

         +353 87 2393010

6      +353 21 4822028

*    j.robinson at kepler-systems.com 

 


  _____  


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