[vtkusers] Re: How to measure the volume from the many objects separated

[Cory Quammen]

Could you attach a picture of your isosurface to make it clearer what
you are trying to do?

Thanks,
Cory

On Fri, Feb 29, 2008 at 8:16 AM, walmor godoi <wfisico at yahoo.com.br> wrote:
> Grateful for the help,
>
>  Interesting this TetGen library...
>  But I need to get the volume of holes (the 12) separately. Each holecylindrical design has different sizes (the smallest has a diameter of1 mm). I need to get the measure of the volume for each.
>   So, how to measure the volume of them separately? Does anyone have any idea?
>
>  Walmor
>  ----- Mensagem original ----
>  > De: Cory Quammen <cquammen at cs.unc.edu>
>  > Para: walmor godoi <wfisico at yahoo.com.br>
>  > Cc: vtkusers at vtk.org
>  > Enviadas: Quarta-feira, 27 de Fevereiro de 2008 15:59:35
>  > Assunto: Re: [vtkusers] How to measure the volume from the many objects separated
>  >
>  > You could tetrahedralize the volume within isosurface and sum up the
>  > volumes of the tetrahedra in the result. I believe the vtkDelaunay3D
>  > won't do the job in this case because it ignores the surface
>  > information in your isosurface, constructing a Delaunay
>  > tetrahedralization from  just the point information. I have used the
>  > TetGen library (http://tetgen.berlios.de/) to generate what's called a
>  > constrained Delaunay tetrahedralization. This fills only the space
>  > interior to your isosurface with tetrahedra. The only requirement is
>  > that your isosurface has no holes, which is most like the case with
>  > output from marching cubes (unless the isosurface intersects the edge
>  > of the entire volume).
>  >
>  > I have wrapped TetGen inside a VTK class to make it easy to use with
>  > the output of things like the marching cubes filter. I could send it
>  > to you, but you would have to set up a vtkLocal build, which may or
>  > may not be something you want to do.
>  >
>  > Hope that helps,
>  > Cory
>  >
>  > On Wed, Feb 27, 2008 at 1:10 PM, walmor godoi  wrote:
>  > > Hi,
>  > >
>  > >  I need estimate the volume and area from a phantom (a acrylic cylinder with
>  > 12 holes in cylinder format too).
>  > >
>  > >  After the reconstruction by Marching Cubes of the phantom with 12 holes
>  > (cilinder format), successfully, i used thevtkMassProperties for measures of
>  > volume and surface area. But the volume and area was the extentof the entire
>  > cylinder which contains the twelve holes, i.e.,  vtkMassProperties just seeing
>  > the cylinder without the holes (I believe because theactors-holes should be
>  > targeted or labelled so they can beindependently measured and it will be the
>  > goal now).
>  > >
>  > >
>  > >  Does anyone have an example of how to measure the volume from the many
>  > objects separated ?
>  > >
>  > >
>  > ----------------------------------------------------------------------------------
>  > >  Walmor Cardoso Godoi, M. Sc.
>  > >  Curitiba - Paraná - Brazil
>  > >  Msn: walmorgodoi at hotmail.com
>  > >  Url: http://walmor.godoi.goglepages.com
>  > >  Blog (visite!): http://walmorgodoi.blogspot.com
>  > >
>  > ----------------------------------------------------------------------------------
>  > >
>  > >
>  > >
>  > >
>  > >
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>  >
>  >
>  >
>  > --
>  > Cory Quammen
>  > Department of Computer Science
>  > University of North Carolina at Chapel Hill
>  > http://www.cs.unc.edu/~cquammen
>  >
>
>
>
>
>       Abra sua conta no Yahoo! Mail, o único sem limite de espaço para armazenamento!
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>



-- 
Cory Quammen
Department of Computer Science
University of North Carolina at Chapel Hill
http://www.cs.unc.edu/~cquammen