[vtkusers] Make Smooth Isosurfaces

[Sanket Jain]

Ok. I will recheck my matlab program which writes the vtk file and get back
to you.

For Paraview, did you mean only the mesh points without the scalar values? I
checked the unstructured grid with scalars on them. They look exactly the
same as in my VTK code.

Sanket

On Fri, Oct 30, 2009 at 7:55 AM, Bill Lorensen <bill.lorensen at gmail.com>wrote:

> Perhaps your scalar values are not associated with the proper points?
> Have you looked at the original unstructured grid with paraview?
>
> On Thu, Oct 29, 2009 at 10:21 PM, Sanket Jain <jainsanket1 at gmail.com>
> wrote:
> > Yes, I tried for number of isovalues. But all of them have similar
> > characteristics. Is it anything to do with the vtk file being in
> > unstructured grid rather than polygonal data? For the mesh, I imported
> from
> > COMSOL, I cannot use polygonal data.
> >
> > Sanket Jain
> > On Thu, Oct 29, 2009 at 6:33 PM, Bill Lorensen <bill.lorensen at gmail.com>
> > wrote:
> >>
> >> It does look strange. Have you tried changing the isosurface value?
> >>
> >> On Thu, Oct 29, 2009 at 5:44 PM, Sanket Jain <jainsanket1 at gmail.com>
> >> wrote:
> >> > I have attached a snapshot of my viewer. The isosurface is predicting
> >> > the
> >> > volume activated during monopolar stimulation. So, theoretically you
> >> > will
> >> > expect a sphere at a particular iso value.
> >> >
> >> > I tried using vtkPolyDataNormals. The figure attached is the output
> >> > after
> >> > including this filter. But I still think this is not smooth.
> >> >
> >> > I verified by opening my vtk file in Paraview (with, Compute Normal
> ON).
> >> > Even then i get the same kind of response. So, do you think this is
> the
> >> > best
> >> > i can get? Or there might be some problem in the vtk file which is
> >> > exported
> >> > from COMSOL (I verified it multiple times).
> >> >
> >> > Thank you,
> >> >
> >> > Sanket
> >> >
> >> > On Thu, Oct 29, 2009 at 4:01 PM, Bill Lorensen <
> bill.lorensen at gmail.com>
> >> > wrote:
> >> >>
> >> >> Sorry, reading your e-mail in more detail. Are you generating the
> >> >> isosurfaces in vtk using vtkContourFIiter or some equivalent. If so,
> >> >> you should run the output through vtkPolyDataNormals.
> >> >>
> >> >> On Thu, Oct 29, 2009 at 4:59 PM, Bill Lorensen
> >> >> <bill.lorensen at gmail.com>
> >> >> wrote:
> >> >> > What do you mean by rough? Perhaps the faces are flat shaded? How
> are
> >> >> > you displaying the model in vtk?
> >> >> >
> >> >> > Are your isosurfaces composed of only triangles? If so, did you
> >> >> > provide surface normals at each point?
> >> >> >
> >> >> > On Thu, Oct 29, 2009 at 4:30 PM, Sanket Jain <
> jainsanket1 at gmail.com>
> >> >> > wrote:
> >> >> >> Hello Experts,
> >> >> >>
> >> >> >> I have just started to use VTK to fulfill my visualization needs.
> I
> >> >> >> am
> >> >> >> trying out few fundamental steps which would be crucial for my
> >> >> >> future
> >> >> >> development.
> >> >> >>
> >> >> >> I exported an  Finite Element Model (FEM) from COMSOL and wrote it
> >> >> >> as
> >> >> >> vtk
> >> >> >> unstructured grid in matlab (points, connections and data). I am
> >> >> >> just
> >> >> >> trying
> >> >> >> to read my vtk file and trying to visualize the isosurfaces at
> some
> >> >> >> value.
> >> >> >>
> >> >> >> The problem is the isosurfaces are very rough even when I
> increased
> >> >> >> the
> >> >> >> mesh
> >> >> >> density in my COMSOL model. I tried to perform the same task in
> >> >> >> paraview and
> >> >> >> even there i saw the same problem.
> >> >> >>
> >> >> >> Do you think that increasing the mesh density should solve it? I
> >> >> >> cannot
> >> >> >> increase the mesh density because of computational issues. Any
> ideas
> >> >> >> on
> >> >> >> this
> >> >> >> problem will be appreciated.
> >> >> >>
> >> >> >> Thank you,
> >> >> >>
> >> >> >> Sanket Jain
> >> >> >>
> >> >> >> _______________________________________________
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> >> >> >>
> >> >> >
> >> >
> >> >
> >> >
> >> > --
> >> > Sanket Jain
> >> >
> >
> >
> >
> > --
> > Sanket Jain
> >
>



-- 
Sanket Jain
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