[vtkusers] vtkLookupTable with vtkStructuredPoints or vtkStructuredGrid : How it works ???

[REGAT-BARREL Aurélien]

Hello, 
Once I have built my vtkStructuredPoints, I threshold it and get the output which I map with a vtkDataSetMapper and then I render it. My vtkStructuredPoints is forgotten.  If the user doesn't want to filter empty points (too long), I simply display my vtkStructuredPoints via a vtkDataSetMapper. It is very simple.  My structured points are built like that :
 
    points->SetDimensions( Grid.X1sup(), Grid.X2sup(), Grid.X3sup() );
    points->SetOrigin( 0.0, 0.0, 0.0 );
    points->SetSpacing( 1.0, 1.0, 1.0 );

    for ( int z = Grid.X3sup() - 1; z >= 0; --z )
    {
        for ( int y = Grid.X2sup() - 1; y >= 0; --y )
        {
            for ( int x = 0; x < Grid.X1sup(); ++x )
           {                
                unsigned char val = Grid.val( x, y, z );         
                scalars->InsertNextValue( val );
           }
      }
    }
    points->GetPointData()->SetScalars( scalars );

No more no less.

About immediate mode rendering, should I turn it on or off, and how ?
What about other filters than threshod ?
I effectively just want to render the boundary of my initial object. That's why I use a threshold. How to do it better ?
Thanks for your help.
 
Aurélien REGAT-BARREL
 

Lisa Avila <lisa.avila at kitware.com> wrote:
Hello,

I am not sure what method you are using to display your structured points data set. Once you threshold to get a structured grid you have a lot of primitives - perhaps when you display the structured points you are rendering only the boundary and with the structured grid you are rendering all cells? That would cause a significant slowdown. Also keep in mind that the first render may take longer than subsequent ones when immediate mode rendering is off  (display lists are being used) - this is the time to build the display list. 

If you only want to render the boundary there are filters you can use to extract that. If you want to render all the cells, then you should consider using volume rendering on the original structured points.

Lisa

At 09:43 PM 2/8/2004, REGAT-BARREL Aurélien wrote:
Hello,
Actually, I am working on a 512*121*60 = 3.7 millions of points. It may be more later...
You can see a resume of my situation here :
http://coding.bug.free.fr/vtkusers/

Lisa Avila <lisa.avila at kitware.com> wrote:


   Hello,


   How big is your data? (the dimensions of the structured points object) 


   Lisa


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