Split mesh filter

Is there any way to split a mesh? Like the clip filter but keeping both sides of the clip. Essentially just want to be able to split a mesh using my distance field scalar.

Why not simply apply two clip filters, inverting one of them? You can combine the result from the two filter using Merge Blocks or something like that if you still want to treat it as a single dataset for further processing.

Hi Utkarsh,

Yes - that is what I have been trying to do (using the clip feature) then I append the 2 or 3 datasets, and then tried using “clean to grid” and/or “clean cells to grid”, but was still seeing surfaces in the middle of the mesh where presumably the nodes have not been merged, and there are duplicate faces. Regards Giles

Add a little tolerance when you apply “Clean To Grid”. Setting the tolerance to 0.0001 or something very low based on your data bounds should help better merge the coincident points on the shared face to avoid the middle seam.

the issue now is that if I use a more recent version of Paraview (with the merge points tolerance option) the VTK file that is created is a newer format, which doesnt work in the “vtkUnstructuredToFoam” tool that Im using. The new VTK has a large section labelled CONNECTIVITY which isnt in the old VTK format. The VTK is not backwards compatible.

what would be good (for me at least) would be a modification to the clip filter which would allow the user to keep “both” sides of the clipped mesh.

Hi @garcfd ,

vtkDataWriter supports to write data to old version of the format using SetFileVersion but it is not exposed in ParaView. It would be trivial to do so, you can even do it with a python plugin.

https://vtk.org/doc/nightly/html/classvtkDataWriter.html#a1f7e734db139322d0c902c9e36b64782

Best,

Thanks Matt,
Is it correct that new VTK format can handle polyhedral cells, but the old VTK cannot?
Regards Giles

poly
…because I found this polyhedral cell which I can save in “new” VTK format ok…
but if I try save in old VTK format the poly cell becomes distorted / messed-up.