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<div>Thank you Ken, that was exactly the reply I was hoping for. I used the extraction tool to remove the unwanted cells, but I will also investigate the first two steps too.</div>
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<div>Many thanks,</div>
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<div>Neil<br>
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<div><span style="background-color: rgba(255, 255, 255, 0);">Dr Neil Ashton MEng (hons), PhD CEng MIMechE</span></div>
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<div><span style="background-color: rgba(255, 255, 255, 0);">Research Engineer</span></div>
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<div><span style="background-color: rgba(255, 255, 255, 0);">Computational Fluid Dynamics Group</span></div>
<div><span style="background-color: rgba(255, 255, 255, 0);">School of Mechanical, Aerospace and Civil Engineering </span></div>
<div><span style="background-color: rgba(255, 255, 255, 0);">University of Manchester</span></div>
<div><span style="background-color: rgba(255, 255, 255, 0);">Manchester</span></div>
<div><span style="background-color: rgba(255, 255, 255, 0);">M60 1QD</span></div>
<div><span style="background-color: rgba(255, 255, 255, 0);">UK</span></div>
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On 6 Nov 2013, at 16:09, "Moreland, Kenneth" <<a href="mailto:kmorel@sandia.gov">kmorel@sandia.gov</a>> wrote:<br>
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<div>The problem you have is that you have no way to define what the outer boundaries of the shape are. As a human looking at the shape, I can reasonably guess that the space in the middle bottom of the data is supposed to be empty. But even then I'm not totally
sure where the boundary is. I don't think there is any reasonable way a filter can predict where there is or isn't supposed to be data. The Delaunay filter makes the reasonable (but often wrong) assumption that mesh should cover the convex hull. However, the
convex hull is conservative in that the result will always cover the space that should be covered plus some extra. So perhaps the easiest thing to do is remove the extra. I can think of three possible ways to do this.</div>
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<div>First, you mentioned that you have a CFD solver. I presume that means you have a proper mesh for the CFD solver. Bring in that mesh and then run the Resample With Dataset filter with the results of the Delaunay2D as the Input and the CFD mesh as the Source.
This will give you the CFD grid with the experimental values interpolated on the points.</div>
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<div>The second thing you could try is to remove "bad" triangles. In you image I notice that most if not all of the polygons in the "empty space" region are either unusually large or unusually thin. You can use the Mesh Quality filter to get the area and aspect
ratio of the triangles and then use the threshold filter to remove the triangles that are unusually large or thin.</div>
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<div>The third thing you could try is to simply use the extract selection filter to get the cells you want. Use the "Select Cells On" tool to select the empty region of the data, then invert the selection, then run the Extract Selection filter.</div>
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<div>I hope that helps.</div>
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<div>-Ken</div>
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<span style="font-weight:bold">From: </span>Neil Ashton <<a href="mailto:neil.ashton@manchester.ac.uk">neil.ashton@manchester.ac.uk</a>><br>
<span style="font-weight:bold">Date: </span>Wednesday, November 6, 2013 7:24 AM<br>
<span style="font-weight:bold">To: </span>"<a href="mailto:paraview@paraview.org">paraview@paraview.org</a>" <<a href="mailto:paraview@paraview.org">paraview@paraview.org</a>><br>
<span style="font-weight:bold">Subject: </span>[EXTERNAL] [Paraview] Delaunay 2D question<br>
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Hi all,
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<div>I have a query regarding the optimal way of visualising some point data from an experiment & CFD.</div>
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<div>I have several 2D PIV windows from an experiment which have between 100 and 800 points arranged at several x and y locations. In order to compare these against CFD simulations I output the data from the same points in the CFD solver.</div>
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<div>To visualise them I currently use the CSV reader, table to points, and then the Delaunay2D filters to turn this data into 2D slices. </div>
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<div>The problem I have is when I have a gap in the data i.e the shape is not a square but has an empty bit in the middle. The Delaunay 2D filter triangulates all the data and it therefore doesn't constrain to the boundaries of the data.</div>
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<div>I have attached three files which hopefully illustrate my problem.</div>
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<div>I wanted to ask if there is a way to constrain the Delaunay2D filter or use an alternative method to ensure that the shape of the PIV/data window is preserved. I'm sure this type of thing is done fairly regularly but I couldn't figure out how to do this
in Paraview.</div>
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<div>Many thanks,</div>
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<div>Neil</div>
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<div><ahmed-surface.png><ahmed-points.png><ahmed-wireframe.png></div>
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<div style="font-family: Verdana; ">Dr Neil Ashton MEng (hons), PhD CEng MIMechE</div>
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<div style="font-family: Verdana; ">Research Engineer</div>
<div style="font-family: Verdana; "><br>
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<div style="font-family: Verdana; ">Computational Fluid Dynamics Group</div>
<div style="font-family: Verdana; ">School of Mechanical, Aerospace and Civil Engineering </div>
<div style="font-family: Verdana; ">University of Manchester</div>
<div style="font-family: Verdana; ">Manchester</div>
<div style="font-family: Verdana; ">M60 1QD</div>
<div style="font-family: Verdana; ">UK</div>
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