[Paraview] 3D vector & contour plots from a set of scattered point

[Eric E. Monson]

Hey Nima,

I don't know if this will be a useable solution for you, but based on  
your notes I tried generating a point cloud (centered on the origin,  
100 points with radius 10) in ParaView, then using the calculator  
filter I generated a scalar value on each node which is the magnitude  
of the x, y, z coordinate vector: mag(coords). Instead of trying to  
sample the data points onto a regular grid, I used the Delaunay3D  
filter (with default parameters) to generate tetrahedra, which can be  
used for volume visualization, contouring, etc. Here is a screen shot  
of the point cloud colored by that vector magnitude (blue-white-red  
colormap), and six contours which have been clipped to show the insides.

Again, not sure if this is the type of solution you were looking for,  
but it interpolates the vector magnitude values and allows you to  
generate contours.

Talk to you later,
-Eric

------------------------------------------------------
Eric E Monson
Duke Visualization Technology Group


On Nov 28, 2009, at 3:25 PM, Nima Emadi wrote:

> Thanks a lot Sven,
> I could generate vector plots. Still trying to find a way to do 3D  
> contour plots for my scattered points. As you said I need to have a  
> mesh and to interpolate my scalar value to nodes of that mesh. Does  
> anyone have an idea to do that?
>
> Best,
> Nima.
>
> On Sat, Nov 28, 2009 at 1:07 PM, Sven Buijssen <sven.buijssen at tu-dortmund.de 
> > wrote:
> Nima,
>
> Your first question has been discussed last month on this list, have  
> a look at
> http://markmail.org/message/36223zg4uleibiyj. David found the time  
> to put the
> question in FAQ style into the ParaView wiki. So, you can also look at
> http://www.paraview.org/Wiki/Display_points_and_normals_from_a_plain_text_(x_y_z_nx_ny_nz)_file
>
> I haven't faced the problem yet you describe in your second  
> question. I'm
> guessing you'll have to import your scattered data into ParaView  
> (e.g. as CSV
> data) and somehow come up with a regular grid in ParaView. This  
> might be
> possible using a Programmable Source or Sources - Data Object  
> Generator, but I'm
> not sure of that. Maybe someone else can point this out. Once you  
> have a regular
> grid, use the Resample with Dataset filter to interpolate your point  
> data set(s)
> to the regular grid and apply the Contour filter.
>
> Hope this helps.
>
> Sven
>
>
> Nima Emadi wrote, On 11/28/2009 12:01 PM:
> > Dear all,
> > I would like to generate 3D vector plots from a set of scattered  
> data in
> > space (an ASCII file with x,y,z,u,v,w). I guess this should be  
> rather
> > simple, but later on I want to generate 3D contour plots out of my  
> data
> > (e.g. having contours based on the value of u^2+v^2+w^2 at each  
> point).
> > Since I just have the value on scattered points in space, making  
> those
> > contours will probably require extrapolation of my data to nodes  
> of a
> > (regular) mesh. My question is that, how can I do those plots? with
> > which format should I import my data? Is paraview able to make  
> contour
> > plots with scattered data points in 3D?
> >
> > Thanks,
> > Nima
> >
> >
> >  
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