[vtk-developers] New nonlinear celltypes

[David C. Thompson]

On Mon, 2006-01-09 at 13:33, John Platt wrote:
> ... I have just had a quick look at the version of
> vtkQuadraticHexahedron::Contour() I am using from 4.4. The call to the
> linear Hex contouring
> 
>     this->Hex->Contour(value,this->Scalars,locator,verts,lines,polys,
>                        this->PointData,outPd,this->CellData,0,outCd);
> 
> takes the local PointData and CellData from Subdivide(). Your call
> 
>     this->Hex->Contour(value,this->Scalars,locator,verts,lines,polys,
>                        inPd, outPd, inCd, cellId, outCd);
> 
> passes the dataset point and cell data.
You know, I looked at that and assumed that all Subdivide() did was make
a local copy with 27 instead of 20 nodes. Since the 27-node hex didn't
need to generate mid-face and body points, I thought it would be OK to
pass them directly and didn't even think about indexing, but you're
right... that might cause trouble.

> I don't know if this has changed at version 5.
Nope. Although as of 4.4.2, there was a bug in clipping and contouring
preventing them from working on more than a single cell because the
point ids were being set incorrectly. It looks like Soeren got that part
right. To see the difference run 
  cd VTK/Common
  cvs diff -r 1.21 -r 1.22 vtkQuadraticHexahedron.cxx

	David