ParaView collections

A ParaView collection file (extension .pvd) represents a time series of VTK files. This may be used for visualising simulation results at different time steps, and in particular for creating simulation movies.

A pvd file is initialised using paraview_collection:

pvd = paraview_collection("my_pvd_file")

By default this overwrites existent pvd files. To append new datasets to an existent pvd file, set the append option to true:

pvd = paraview_collection("my_pvd_file"; append = true)

VTK files are then added to the pvd file with

pvd[time] = vtk

or equivalently

collection_add_timestep(pvd, vtk, time)

Here, time is a real number that represents the current time (or timestep) in the simulation. Note that both options implicitly call vtk_save(vtk) so adding the VTK file to the collection must be done after adding data to the file.

When all the files are added to the pvd file, it can be saved using:

vtk_save(pvd)

Working example

The following is a full working example using the do-block syntax:

x, y, z = 0:10, 1:6, 2:0.1:3
times = range(0, 10; step = 0.5)

saved_files = paraview_collection("full_simulation") do pvd
    for (n, time) ∈ enumerate(times)
        vtk_grid("timestep_$n", x, y, z) do vtk
            vtk["Pressure"] = rand(length(x), length(y), length(z))
            pvd[time] = vtk
        end
    end
end

In this example, the saved files are:

julia> saved_files
22-element Vector{String}:
 "full_simulation.pvd"
 "timestep_1.vti"
 "timestep_2.vti"
 "timestep_3.vti"
 "timestep_4.vti"
 "timestep_5.vti"
 "timestep_6.vti"
 "timestep_7.vti"
 ⋮
 "timestep_15.vti"
 "timestep_16.vti"
 "timestep_17.vti"
 "timestep_18.vti"
 "timestep_19.vti"
 "timestep_20.vti"
 "timestep_21.vti"

Acknowledgements

Thanks to Patrick Belliveau for the initial implementation of ParaView collection functionality, and to Sebastian Pech for additional improvements.