Hi David,
I guess I am a bit surprised at the significant jump in memory, although
I suppose I shouldn't be in thinking about it in more detail. Thanks for
doing the math 8-)
Given the above, it isn't really practical to use the clip filter on
volume data set sizes of significant size unless you have a mondo big
memory computer. At the same time, clipping is a very powerful technique
for exploration. It is one of my favorite filters to use when looking at
a new dataset.
Utkarsh suggests using "Extract Subset" or "Slice" but both are somewhat
limited compared to an arbitrary clip plane. Extract subset results in
clipping only along the data set axes and slice doesn't show internal
structure around the slice plane.
Are there any other alternatives to getting an arbitrary clip plane on a
large volume data set without blowing out the memory? Has anyone come up
with any clever tricks?
For me this is mostly curiosity driven, as I am no longer working on the
project that sparked my Dec 2012 email, but clearly there are some
people that are struggling with this issue still (e.g. Robert).
Brian
On 6/10/2014 11:03 AM, David E DeMarle wrote:
On Tue, Jun 10, 2014 at 12:41 PM, Brian Corrie <[email protected]
<mailto:[email protected]>> wrote:
Hi All,
I have one question regarding this conversation, as I have run into
this issue before. It intrigues me as to why one can't clip a
structured data set efficiently.
http://www.paraview.org/__pipermail/paraview/2012-__December/026976.html
<http://www.paraview.org/pipermail/paraview/2012-December/026976.html>
The question I have is - does clip REALLY require all that memory -
in my case it was a structured grid of 698x693x665 growing to in
excess of 20 GB (see the question on the list above). That seems
pretty excessive given the original size of the data set... I
haven't done the math on the data set size of an unstructured data
set, but 320MB to 20GB is a pretty big step.
Very likely.
imagedata
origin + extent + spacing ~= 36 bytes #(x,y,z + ni,nj,nk + sx,sy,sz) *
4bytes per word
(700^3 * 4)/(1024^3) = 1.27 GB #to store one scalar value on each point
unstructured grid
points array = (700^3 * 3 * 4)/(1024^3) = 3.8 GB #3=x,y,z, 4=4bytes per word
cellarray = (699^3 * 9 * 4)/*(1024^3) = 11.45GB, #1 numverts + 8 vertex
index
celltype = (699^3 * 4)/(1024^3) = 1.27GB
celllink = (700^3*9*4)/(1024^3) = 11.5GB #1 numcells + 8 using cells per
vert
(700^3 * 4)/(1024^3) = 1.27 GB #to store one scalar value on each point
(Someone check me on all of that please).
T
But yes, a clip like widget to something like Extract Subset that is
easy to use AND preserves the data type would be a really nice thing to
have in ParaView.
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