[vtkusers] VTK 4.2 - Unstructured grid, quadratic cells

[Will Schroeder]

Hi John-

Thanks for the feedback, I'll look into this. I would not be surprised if 
there are some problems since the quadratic cells are a recent addition to VTK.

To view a quadratic edge as a "parabola" you could sample (in parametric 
space) along the edge and generate points along with a polyline and display 
that.

Will

At 10:17 AM 5/7/2003 +0100, john platt wrote:
>Hi VTK users,
>
>This is my first excursion into VTK so apologies in advance if this is not 
>the correct forum.
>
>I am working with QUADRATIC cells (2D/3D) in unstructured grids and 
>require a view of all the cell edges. I hit a couple of snags along the way.
>
>1. vtkQuadraticQuad.cxx (revision 1.15) - about line 70 in GetEdge() : 
>typo - the modulus should be 4 (the number of edges).
>
>2. vtkExtractEdges.cxx (revision 1.44) - about line 123 in Execute() : 
>loop over the number of points along an edge assumes a point order in 
>increasing distance along the edge (first, next, ... last) whereas 
>GetEdge() returns (first, last, next...). Swapping the last and mid-side 
>nodes in the edge list gives me the required view of all the cell edges.
>
>Unfortunately, my build of the Windows debug dll's leak memory. I am using 
>W2K Professional MSVC6 s/p2ish. Is this likely to be a problem with the 
>s/p level ?
>
>What I would like is to display the quadratic cell edges as parabolas and 
>not 2 linear segments. Can anybody point me in the right direction?
>
>Many thanks.
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