How to read .vtu files?

Question

I see the Import function can import .vtk files. But how about .vtu files? Is there an existing package for this?

Answer 1

To the best of my knowledge, there is currently (Mathematica v. 14.0.0.0) no package to read .vtu files. However, you can exploit the structure of the file to write your own reader function after you Import[] it as a "Table".

For instance, let's assume you have a file with the following structure:

<?xml version="1.0"?>
<!-- time 0.0399642-->
<VTKFile type="UnstructuredGrid" version="0.1" byte_order="LittleEndian">
<UnstructuredGrid>
<Piece NumberOfPoints="3220" NumberOfCells="0">
<Points>
  <DataArray type="Float32" Name="Position" NumberOfComponents="3" format="ascii">
    0.238845 0.025684 0.173811
    0.224136 -0.11521 0.135539
    0.278716 0.215721 -0.213643
...
</DataArray>
</Points>
<PointData  Vectors="vector">
  <DataArray type="Float32" Name="Velocity" NumberOfComponents="3" format="ascii">
 0 -0.391767 0
 0 -0.391767 0
 0 -0.391767 0
...

A simple, very low-level code that reads the position and velocity of nP particles (where the number of particles in each file can differ) is the following:

data = Import[<file_name>, "Table"];

nP = ToExpression[StringSplit[data[[5, 2]], "\""][[2]]];
n0 = 8;
n1 = n0 + nP + 4;

positions = data[[n0 ;; n0 + nP - 1]];
velocities = data[[n1 ;; n1 + nP - 1]];

where n0 and n1 are the lines where the data you need is written. I hope this will help.