How does paraview read a vtk file?

Question

I have a general question as to how paraview reads a ASCII UNSTRUCTURED_GRID.

Does it sort through the cells and then points? or points then cells?

Hautrhin

What do you mean by "sort through"? – Thessalonians

@CoryQuammen does it get the value from the cells then find the points from that? or does it pick a point and find the cell from that? – Hautrhin

I think you have some assumptions that I don't understand. What are you trying to accomplish? Maybe that would be a better starting point. Are you trying to write a file that ParaView can read, for instance? – Thessalonians

Answer 1

Paraview is built on the VTK library and both of them are open source, so if you are a programmer, you should be able to get all your answers by reading the code. What I assume (but I can be wrong, check sources of paraview to be sure) paraview uses for reading ASCII unstructured grids is vtkUnstructuredGridReader, source code of which you can find here: https://github.com/Kitware/VTK/blob/master/IO/Legacy/vtkUnstructuredGridReader.cxx (and here is the parent class that implements a lot of the functionality the reader uses https://github.com/Kitware/VTK/blob/master/IO/Legacy/vtkDataReader.cxx). Look at the RequestData method, the variable "output" is the outputted unstructured data.

To briefly answer your initial question, it looks like points are read before cells.

Adest