Export nodal data to VTK format

[CsatiZoltan]

Hi,

I tried to plot the displacement field in Neper. What I realized was that using the -datanodecol option only, without providing element visualization using for example the -dataelt3dcol option, the PNG output defaults to the colour of the element sets. It is possible to plot the displacement field by interpolating the nodal values on the elements, so

-dataelt3dcol from_nodes
-datanodecol disp1

works fine for the PNG output. On the other hand, no (nodal or interpolated element) data is written to the VTK file, when I specify the image format to be vtk.

How can I export the displacement field into a VTK file? The same observations apply to other nodal data as well, such as the coordinates.

Thank you,
Zoltan

EDIT: If nodal data could be output into VTK format, that would allow one to export the coordinates as well, hence supporting the visualization of the deformed configuration.

[rquey]

Hi,

I tried to plot the displacement field in Neper. What I realized was that using the -datanodecol option only, without providing element visualization using for example the -dataelt3dcol option, the PNG output defaults to the colour of the element sets.

Yes, because -datanodecol defines the colors of the nodes, not the colors of the elements. You could see the (colored) nodes using -shownode 1 (and probably -datanoderad to increase the node radii).

It is possible to plot the displacement field by interpolating the nodal values on the elements, so

-dataelt3dcol from_nodes
-datanodecol disp1

Yes.

works fine for the PNG output. On the other hand, no (nodal or interpolated element) data is written to the VTK file, when I specify the image format to be vtk.

Indeed, no "color data" are written to the VTK file at the moment.

How can I export the displacement field into a VTK file? The same observations apply to other nodal data as well, such as the coordinates.

Thank you,
Zoltan

EDIT: If nodal data could be output into VTK format, that would allow one to export the coordinates as well, hence supporting the visualization of the deformed configuration.

You can use -datanodecoo coo, which plots the deformed mesh in PNG and writes a VECTORS coo data field in the VTK file.

[CsatiZoltan]

@rquey Although I still think it would be useful to add the feature of plotting nodal data (what you called "color data"). I am not pushing it from my side, it is just handy if one could superimpose the original and deformed meshes in Paraview. That would be more elegant than exporting coo from step $n$ and from step $0$ into two .vtk files, and then subtract them using filters.

[rquey]

So, in this case, you would want the disp data in the vtk file, is that it?

[CsatiZoltan]

@rquey Yes.

[rquey]

@CsatiZoltan The -datanodecol data are now written to the vtk file (version 4.2.1-6). They can be of any type (not only scalars), so this will work with disp. If not scalars, you have to disable the png output (-imageformat vtk).

[CsatiZoltan]

Works perfectly! Thank you.