I have created vtk files of each time step but the order is very messed up if I load in Paraview. It looks like that
How to select with the original order?
ParaView sorts the files in a group by their lexicographical order, not their numerical order. So a file named time_1000.vtk will be earlier in the list than time_150.vtk because the 0 after the 1 in the first name is lexicographically earlier than the 5 in the second name.
The easiest solution is to use 0-padding in the numbers in. your file names. For example, if your files were named time_0001.vtk, time_0100.vtk, time_0150.vtk, time_1000.vtk, etc., they would be displayed in the correct order.
ParaView 4.4 was built with Qt4, this may be the reason of this change of behavior.
Looks like a misfeature in the older version. I would expect lexicographical sort (even if a natural sort would be nicer). Sorting based on time-stamps makes things non-reproducible.