[Paraview] some points are not shown

[David E DeMarle]

On Thu, Apr 7, 2011 at 7:34 AM, Bart Vandewoestyne
<Bart.Vandewoestyne at telenet.be> wrote:
> On Thu, Apr 07, 2011 at 06:17:00AM -0400, David E DeMarle wrote:
>> The points representation shows only the vertices of the external
>> cells (ditto for edges representation).
>
> I'm confused.  Looking at the online help at
>
> http://paraview.org/OnlineHelpCurrent/ViewMenu.html#Representation
> http://paraview.org/OnlineHelpCurrent/Display.html#Style
>
> it is written
>
> "[...] Selecting Points displays the vertices of the dataset as points.
> The Wireframe option shows all the edges of the cells in the
> dataset as lines. [...]"
>
> Note that it is written 'the vertices of the dataset' and 'all
> the edges of the cells' from which one (mistakenly?) deduces that
> *all* points and *all* cells are shown?  But apparently this is
> not how it works???

That documentation is incorrect.

ParaView draws everything (well except volume rendered things) by
extracting the external polygonal faces first, then drawing that. So
the points and edges representations do not show internal features.

That documentation is also very dated. The current help can be found
here: http://paraview.org/Wiki/ParaView/Users_Guide/Table_Of_Contents

>
>> Apply a glyph filter with a 2D Glyph -> VERTEX to make the internal
>> ones visible as well.
>
> OK.  This helps.  To get an even better visualization of my
> Points, I've applied a Glyph filter with Sphere as a Glyph Type.
> Now I see all my 20 points, but the wireframe is still wrong:
>
> http://www.kuleuven-kortrijk.be/~bartv/screenshot_paraview.png
>
> Note that:
>
> 1) no interior edges are shown
>
> 2) there are points on the surface of the tetrahedron that are
> not connected to any edge... from which i deduce that the 'cells'
> which are currently visible do not match with the cells that I
> have defined in my .vtu file.

You have overlapping cells. I suspect overrendering hides the edges
that touch those "disconnected" points.

See cell 2 and 11 for example which overlap each other on the -Y
"face" of the object.

>
> How can I make sure that the wireframe representation is
> *exactly* the cell-configuration that I have specified in my .vtu
> file?
>

Use the shrink filter with a factor of 1 and show the wireframe of
that. Use a smaller shrink factor to see the overlap more clearly.

Also, use the spreadsheet view and select/extract individual
points/cells to see what is what.

Another helpful technique is to select points but "Select cells that
include the selected points" on the Selection Inspector.

> Kind regards,
> Bart
>
> --
>        "Share what you know.  Learn what you don't."
>