Reading CGNS files in trame

[wyattnapier]

Hi! I am trying to read CGNS files in trame rather than a vtk or vtu file. I followed the same steps as were listed in the trame-tutorial and I copied most of my code from 04_application/solution.py. However, I modified the import statement such that it now is from vtkmodules.vtkIOCGNS import vtkCGNSReader. Then, I also changed the read line so that reader is defined as follows: reader = vtk.vtkCGNSReader(). However, I am still just getting the error: ModuleNotFoundError: No module named 'vtkmodules.vtkIOCGNS'.

I also tried another implementation where reader = vtk.vtkCGNSReader(), but it results in an error as well: AttributeError: module 'trame.widgets.vtk' has no attribute 'vtkCGNSReader'.

How should I go about fixing this? I am restricted to CGNS files by the nature of my work.

[jourdain]

you may want to do from trame.widgets import vtk as vtk_widgets so you don't confuse the global vtk package with trame.widgets.vtk one.

[wyattnapier]

Hi! Thank you for such a quick response. Unfortunately, that didn't fix the issue.

[jourdain]

My suggestion was to fix the following

import vtk
reader = vtk.vtkCGNSReader()

[jourdain]

Otherwise looking at the module name it should be

from vtkmodules.vtkIOCGNSReader import vtkCGNSReader

[wyattnapier]

Oh, I'm sorry, I guess I misunderstood. The last thing you said worked, so now I'm on to dealing with other issues. Thank you!

[jmythms]

@wyattnapier Did you ever get it to work? If yes, can you share the code?

[wyattnapier]

It was something like this:

from vtkmodules.vtkIOCGNSReader import vtkCGNSReader  
CURRENT_DIRECTORY = os.path.abspath(os.path.dirname(__file__))  
reader = vtkCGNSReader()  
reader.SetFileName(os.path.join(CURRENT_DIRECTORY, "pathname"))  
reader.Update()  

When you go to the documentation page, there is usually a link at the top that is prefaced by "#include" and then in that code you can typically find the module you need to import within such as vtkIOCGNSReader which is where vtkCGNSReader is defined and thus that is why I imported it like that. Additionally, you'll often be suggested to do something like vtk.vtkCGNSReader(), but because in my code I have the line, from trame.widgets import vtk, vuetify, trame it messes things up and you will just want to import the vtkCGNSReader as I did above and then just call it like I did before without the "vtk." before it. Let me know if you have any more questions.

[jmythms]

May I ask if you ended up using a specific Mapper for the cgns reader?

[wyattnapier]

Hi @jourdain! I had one more question about CGNSReaders. I was hoping to upload a file by following this example: https://github.com/Kitware/trame/blob/master/examples/00_howdoi/upload.py. However, if I want to then have that file be the input to my vtkCGNSReader, I have been defining it with the line: reader.SetFileName(os.path.join(CURRENT_DIRECTORY, "pathname")). I tried to copy this implementation below.

@state.change("file_upload")
def file_uploaded(file_upload, **kwargs):
    if file_upload is None:
        return
    file = ClientFile(file_upload)
    file_name = file_upload.get("name")
    ABS_PATH = os.path.abspath(file_name)
    print("absolute path:", ABS_PATH)

    reader = vtkCGNSReader()
    reader.SetFileName(ABS_PATH)
    reader.Update()
    print(reader.GetOutput().GetNumberOfBlocks())

Is there a way that I can pass the file_upload into the vtkCGNSReader?

[jourdain]

yes, you need to write it to disk so you can read from it.