Unable to Open or Create Cases in mfix-23.1 with --novtk flag

Dear mfix team,

I would like to report a bug that I encountered while using mfix-22.3.1.

I am unable to open existing cases and create new cases in the software. I have attached a zip file containing the generated bug report for the errors that occurred when opening a case (this case can be opened in mfix-22.4.3), as well as a screenshot when attempting to create a provided tutorial case.

mfix_2023-04-20T164426.722636.zip (9.5 KB)

It is possible that there is something wrong with the display on my workstation, as I always start mfix using “mfix --novtk”. However, I am not sure if this would cause any errors in mfix-22.3.1. But it works well in previous versions.

Please let me know if there is any additional information that you require to assist with resolving this issue. Thank you for your assistance in this matter.

Hi - thanks for the report and sorry for the trouble. I took the liberty of editing the post title slightly.

I’m afraid the --novtk flag does not work correctly in mfix-23.1, as you have observed. This flag is not widely used and it looks like it has not been tested in a while. I’ll try to get it fixed for the next release.

The --novtk flag was added to MFiX before we started using Conda to manage packages, because in some cases it was seen as prohibitively difficult to install VTK. Now that MFiX is distributed as a Conda package, the VTK libraries and their dependencies all get installed automatically - indeed, looking at mfixversioninfo.txt:

VTK:                 9.2.6

So my question is, why are you not using VTK? What happens if you start mfix without the --novtk flag?

Hi @cgw, I cannot open mfix without the --novtk flag, please see below screenshots.

What if you do


You may find more suggestions at the VTK forum https://discourse.vtk.org since this is really a VTK issue.

It works! Thanks so much! @cgw