Elmer Discussion Forum

Hi

I am working on a 2D plan problem which is delt by Elmer as the boundary condition of a larger 3D computation. I would be glad to get only this boundary when post processing my data with paraview.
So, do you know if it is possible to extract only one boundary from the general geometry in paraview.
I was thinking of slicing my body with respect to the boundary condition index (as done with the grouping in ElmerPost) but these indexes does not seem to be acessible in paraview.

Cheers
Basile

Hi,

did you try the slice filter? There is also a filter called "extract surface" which I have never used.
You may get a better answer if you post your question on the ParaView mailing list http://www.paraview.org/mailman/listinfo/paraview.

HTH,

Matthias

Slice filter will only work on a flat surface which is not the usual for my geometries. The "extract surface" work well when coupled to a "clip" filter to get rid of top and side surfaces but it is still not perfect, I will see if paraview users have more ideas.

Thanks
Basile

Hi,

perhaps you can filter the surface by its material id, defining a "threshold" filter over the cell data (material ids) in the "selection inspector".

Regards,

Cesar

Hi Cesar

There is, if I remember correctly, something like "Mask Variable". If this is living just on the BCs (the permutation vector is only there nonzero) then you can just save the boundaries when using VTU format.

-Peter

Hi Peter

I see the point of your answer but I don't see how to access to the permutation vector in paraview.

Basile

Hi Basile

This is something to be added as a keyword in the Solver section of the ResultOutputSolver. Then only the boundaries where the variable is active will be saved. The permutation vector is not saved and cannot be accessed in Paraview.

-Peter

Hi

I was fearing this answer. In fact I also want to be abble to see the body of my material so your solution does not seem to fit (Or could I run two ResultOutput solver, one for the boundary and one for the all geometry).

Hi

Do you suggestions how the VTU file could be augmented to allow the recognization of BCs?

-Peter

Hi

My first thought were to pick directly the nodeindexes of BC I am interested in in the mesh.boundary file and to create a selection in paraview. But I don't know anything in Python to write the needed macro. So If the BC indexes could be saved in the vtu file this would be perfect.

Basile