Berk,
Thanks for correcting me. I'll try adding the vtkGhostLevels to the
XDMF and see how that goes.
Chris
On Apr 4, 2009, at 2:50 PM, Berk Geveci wrote:
The right way to deal with this situation is to mark the ghost cells
as ghost. If you create a cell array called vtkGhostLevels and assign
0 to inside cells and 1 to ghost cells, you should not need
MergeBlocks or CleanToGrid. Note that this array has to be of type
unsigned char. There are actual benefits to keeping ghost levels since
some algorithms will produce better results.
-berk
On Thu, Apr 2, 2009 at 6:37 PM, Chris Kees
<[email protected]> wrote:
I turned off the overlapping domain decomposition (ghost cells) for
a simple
problem and the sequence
MergeBlocks->CleantoGrid->ExtractSurface->Clip
shows just the physical boundary of the problem (clipped open so
you can see
inside). Also volume visualization and streamline calculation works
with no
processor boundary artifacts.
From what I understand, there are no filters in paraview or
abstractions in
the XDMF data model at this time that will allow paraview to read in
overlapping blocks and really make use of the ghost cells
correctly. For now
truncating our output to only "owned" elements will solve our
problems.
Thanks again for the help.
Chris
On Mar 30, 2009, at 2:06 PM, Chris Kees wrote:
Thanks for the help. I also tried suggestions from Paul, Ken, and
Berk,
but it does seem that I'm stuck right now unless I provide
ParaView with
more information. Since streamlines are computed correctly on the
current
multiblock mesh I just generated the mesh on a single processor
and used
ExtractSurface->Clip on that mesh to visualize the geometry around
the
streamlines from the multiblock grid.
On the first method: Each of my UnstructuredGrids in the
Multiblock Grid
is a subdomain in an overlapping decomposition of the domain. Each
of the
subdomains has several elements of overlap (the layer of ghost
cells is more
than one element thick). Presumably the streamline generation
works now on
the multiblock grid because the overlap is loaded into ParaView.
Is there a
way I can just set a cell-centered attributed to identify the
ghost cells so
that surface extraction and volume visualization will work too?
Currently
volume visualization of the multiblock grid shows only a single
subdomain
and volume visualization after MergeBlocks shows the whole domain
but with
overlap regions being more opaque.
On your other method, we have both the external boundary mesh and a
pre-mesh polygonal representation of the boundaries available in the
simulator. You are suggesting that I just dump one of those to a
valid
ParaView format as well, is that correct?
Chris
On Mar 30, 2009, at 9:14 AM, Jean Favre wrote:
Chris Kees wrote:
So far I've tried MergeBlocks->ExtractSurface->FeatureEdges-
>Clip and
various permutations that I've seen in previous posts and the
wiki,
but I always end up with the surfaces on the interior of the
tank as
if it still sees each subdomain as a closed surface.
In fact, it seems to me that ParaView does the best it can. Your
unstructured mesh is partitioned in 512 pieces and [presumably],
you did
not specify ghost-cells at the partition boundaries. Without
ghost-cells, ParaView has no information to help decide whether an
outside face looks towards the outside world, or to another
partition. I
don't think any combination of filters would help you. Removing
duplicate points may only remove duplicate fake boundaries, but
these
fake boundaries must be removed all together.
I use two methods to achieve what you want. Ghost-cells, or another
multi-piece object containing the different boundary types (solid,
symmetries, inflow, outflow, etc) stored as vtkPolyData. These
are read
in from the models on disk.
Jean --
Swiss National Supercomputing Center
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Please keep messages on-topic and check the ParaView Wiki at:
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