Hi Burrlen, Thank you for your help
Marios On Wed, Dec 4, 2013 at 10:50 AM, Burlen Loring <[email protected]> wrote: > Hi Marios, > > If I apply the InterpolatetoQuadraturePoints filter as shown in > Figure 2 the output result is > basically empty. > > If you write the data arrays containing the scalar values at the Gauss > points to the file then you do not want to apply the "interpolate to qp" > filter. This filter's purpose is to generate these array from nodal values. > This means that you have to have the nodal values. You mentioned that > you've removed them so that you won't get confused, and that will prevent > this filter from working. > > If I apply the GenerateQuadraturePoints filter as shown in Figure 3 the > field data > transformed to point data. Hence after the application of the > GenerateQuadraturePoints the previous 9 > point data and 4 cell data are not exist anymore but together with the > field data they transformed to 16 > point data representing the 16 Gauss points. Those 16 points have the > correct coordinates and T values. > > yes, that's what should happen. You're visualizing a different geometry - > the Gguass points - so data arrays on the original geometry will not be > available. > > > I tried to reproduce the same example using the GID software and > the results are shown in > Figure 4. Can I do something similar with Paraview? I want to have these > contour lines instead of just > point’s information. I want to continue use Paraview because has some > really powerful features that I > like and I am sure this is trivial but I cannot find some way to do it. > > you can't generate the contours on a point set, you first need to mesh it. > One way to do this would be to apply "delaunay 2d" to the point set. Other > approaches would be more efficient and produce better results but would > require you to write some code. eg. write out the mesh on the Gauss points > directly from your simulation. > > > On 12/04/2013 10:30 AM, Marios Mavros wrote: > > Hi Burlen, > > Thank you for your help and for your example that you have provided. I > followed your instructions and I prepare a small pdf explaining what I did > and what I expected as a final result. I thought that this procedure was > the solution to my problem but maybe I have to do something extra or > something different. Attached you will find also the file that I used. > > Thank you again for your help > > Marios > > > On Tue, Dec 3, 2013 at 2:46 AM, Burlen Loring <[email protected]> wrote: > >> >> 1. What the numbers 0 4 8 12 (line 24) represent? >> >> This is the offset array used by VTK for random access into data on the >> quadrature points data. To generate it you go cell by cell and accumulate >> the number of quadrature points used by each cell. The next cell's data >> offset is the sum of the previous cell's number of quadrature points. >> >> note that the documentation says that each array has a quadrature scheme >> dictionary, but this changed. the dictionaries are stored in the offeset >> array. we did this so that you only need to define one quadrature scheme >> dictionary for many arrays. >> >> >> 2. What the QuadratureWeights are all zero (line 37)? >> >> Those aren't currently used in VTK but we have a place holder for them >> in case they are needed in user developed custom filters or later in VTK. >> >> >> 3. In your example there are 4 cells with 4 Gauss points in each cell. In >> total 16 Gauss points. If I want to assign to each Gauss point one value of >> stress or strain how I have to write those 16 values in xml format. >> >> in my example you would read this file into PV and apply "interpolate >> to quadrature points" and then "generate quadrature points". >> >> You're asking about writing the data on the Gauss points into the file. >> You have to store them in VTK FieldData and add an information key to each >> array that names the offset array. You have to order them correctly >> according to the offsets array and quadrature scheme. for example the pdf I >> sent before shows how each cell's quadrature points are ordered for one >> scheme. you won't write the points themselves, just the data values. >> >> the T FieldData array in the following file is an example of containing >> scalar values at quadrature points (watch out there's also a PointData >> array named T that stores the nodal values), >> http://www.hpcvis.com/vis/images/vtk-quadrature-points-example/quadrature-points-example-2.vtu >> >> after reading such a file into PV, you could see the arrays in the >> spreadsheet view but to see them in the 2d/3d view you'll need to apply the >> "generate quadrature points" filter to produce the point set and transfer >> the data onto it. >> >> >> On 12/01/2013 10:26 PM, Marios Mavros wrote: >> >> Hi Burlen, >> >> Your example was really helpful to understand many thing about the xml >> format and I want to thank you about that, but I still have some questions. >> >> 1. What the numbers 0 4 8 12 (line 24) represent? >> 2. What the QuadratureWeights are all zero (line 37)? >> 3. In your example there are 4 cells with 4 Gauss points in each cell. In >> total 16 Gauss points. If I want to assign to each Gauss point one value of >> stress or strain how I have to write those 16 values in xml format. Can you >> please sent me an example with this information? >> >> Thank you very much >> >> Marios >> >> >> On Sat, Nov 30, 2013 at 4:28 PM, Burlen Loring <[email protected]> wrote: >> >>> Hi Mario, >>> >>> sending again to the list. the weights have 2 dimensions i (node id) and >>> j (Gauss point id), so to generate ShapeFunctionWeights for a new >>> QuadratureSchemeDefinition what you do is evaluate each shape function at >>> each Gauss point. For the linear quadrilateral you'll end up with 16 >>> weights. For example see the example >>> >>> >>> http://www.hpcvis.com/vis/images/vtk-quadrature-points-example/vtk-quadrature-points-example.pdf >>> >>> http://www.hpcvis.com/vis/images/vtk-quadrature-points-example/quadrature-points-example.vtu >>> >>> Burlen >>> >>> >>> On 11/29/2013 3:34 PM, Marios Mavros wrote: >>> >>> Hi Burlen, >>> >>> I want to thank you for the information that you send me. I read the >>> paper and I try to made a simple example in xml format for a 4 node >>> quadrilateral element but it didn't work for me. Attached you will find the >>> element formulation that I used with the shape functions and a .vtu file >>> with my example. If I want to give 4 stress values in the 4 Gauss points ( >>> lets say 0.1 0.2 0.4 -0.1) can you please write in the .vtu file the >>> missing information in order to understand haw I have to write a correct >>> file in xml format. >>> >>> Thank you very much >>> >>> Marios Mavros >>> >>> >>> On Wed, Nov 27, 2013 at 2:56 PM, Burlen Loring <[email protected]> wrote: >>> >>>> You'll need to use an XML file format. There's some documentation in >>>> the following link. It's slightly dated but should get you started. >>>> http://www.vtk.org/Wiki/images/7/78/VTK-Quadrature-Point-Design-Doc.pdf >>>> The ctest, VTK/Filters/General/Testing/Cxx/TestQuadraturePoints.cxx, >>>> could be used as an example. >>>> >>>> >>>> On 11/27/2013 02:32 PM, Marios Mavros wrote: >>>> >>>> Hi >>>> >>>> I have wrote a simple program in Fortran that transform the output of >>>> a finite element software in vtk Legacy Format. I don't know how to handle >>>> the Gauss points values. For example in my case my cells have 4 Gauss >>>> points and I have 4 values (for example strain in x-direction) for each >>>> cell. How I have to write the vtk file taking into account that each cell >>>> has many Gauss points? >>>> >>>> Thank you >>>> >>>> Marios >>>> >>>> >>>> _______________________________________________ >>>> Powered by www.kitware.com >>>> >>>> Visit other Kitware open-source projects at >>>> http://www.kitware.com/opensource/opensource.html >>>> >>>> Please keep messages on-topic and check the ParaView Wiki at: >>>> http://paraview.org/Wiki/ParaView >>>> >>>> Follow this link to >>>> subscribe/unsubscribe:http://www.paraview.org/mailman/listinfo/paraview >>>> >>>> >>>> >>> >>> >> >> > >
_______________________________________________ Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the ParaView Wiki at: http://paraview.org/Wiki/ParaView Follow this link to subscribe/unsubscribe: http://www.paraview.org/mailman/listinfo/paraview
