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vensim .mdl extension applied to flight sim files

Posted: Wed Aug 14, 2019 5:33 pm
by PeterHeffron
I am using Windows 10 on a Dell computer, and Vensim PLE.

Recently I attempted to use Prepar 3D V4 flight simulator, and the program 'crashed' (no pun intended). This was after I had worked on a causal loop diagram in Vensim PLE.

I searched the Prepar 3D files for a possible source of the crash. I found that all of the sim airplanes had been renamed as Vensim files, probably due to the aircraft and Vensim using the same file extension (".mdl"). Example: AIRCRAFT: "Beech_Baron_58 Vensim.mdl" (airplane in Prepar 3D V4 flight sim) AND VENSIM MODEL: "World3-Population" (Vensim.mdl).

Uninstalling Vensim PLE did not solve the problem, so I had to reinstall a full mirror backup of my hard-drive, and have not dared re-download Vensim PLE, which I sorely miss!

Has anyone else experienced this -- and is there a solution, whereby I can have both Vensim PLE and Prepar 3D flight simulator on my computer?

Thank you! -- Peter Heffron.

Re: vensim .mdl extension applied to flight sim files

Posted: Wed Aug 14, 2019 8:36 pm
by tomfid
Vensim does register for the mdl file time when installed, but on Windows the file type really has no effect on a program's access to a file. There's no "renaming" involved. So, I don't see how that could affect your simulator's performance.

What was the specific symptom of the crash? Is there an error log that might shed some light on this?

Re: vensim .mdl extension applied to flight sim files

Posted: Thu Aug 15, 2019 7:16 am
by Administrator
My guess is that you are double clicking on a MDL file, and this is starting up the wrong application (flight sim instead of Vensim?).

All I can suggest is starting the application via it's shortcut, then using File->Open to open the correct file.

The other alternative is to register MDL files as using the flight sim, a Google search for file associations will give you info on how to do this.

Re: vensim .mdl extension applied to flight sim files

Posted: Fri Aug 16, 2019 6:19 pm
by PeterHeffron
Thank you for your suggestions. -)

I tried pretty much everything, including a series of steps to disassociate the file extension from any app, but the processes turned out to be too convoluted for me (a patience and anxiety issue). I'm attaching two screenshots that might help you see what is happening. The original flight sim file in the screenshot example has a .mdl extension, but is not associated with and program/app. After installing Vensim PLE, it automatically changed to a .mdl Vensim file, associated with Vensim.

I was then unable to change it back to an unassociated .mdl file. Also, I suspect that if I were to be able to right-click on the now modified flight sim .mdl file using "Open as" and assign it to another app/program -- that, perversely, all of my Vensim .mdl files would then be 'corrupted' in the same way.

I wonder if I'm the only Vensim user who also flys the Prepar 3D v4 flight simulator, where both programs share the .mdl extension?

Unless you can think of a not too complicated fix, I'm guessing I'll have to delete either Prepar 3D or Vensim from my computer, which would be sad.

Thanks again!
Peter Heffron
Norway

Re: vensim .mdl extension applied to flight sim files

Posted: Fri Aug 16, 2019 7:16 pm
by Administrator
You can only have one application associated with MDL files.

But that doesn't really matter. Don't double click the files. If it's a Vensim model, start Vensim using the shortcut to it, then click File->Open and browse to the model.

I'm not familiar with the flight sim, but there must be a similar way to do this in the sim. Start it using a shortcut (don't double click the MDL file) and click File->Open.

Re: vensim .mdl extension applied to flight sim files

Posted: Fri Aug 16, 2019 7:29 pm
by tomfid
If your flight simulator is still choking on this somehow, my recommendation would be to re-associate the files with the flight simulator. Then you will have the reverse problem, that you won't be able to open a Vensim model via a double-click in Explorer. But you'll still be able to open models from within Vensim (File menu) or via a right-click > Open With... in Explorer.

Unfortunately this is a design problem in Windows that we can't do much about.

Re: vensim .mdl extension applied to flight sim files

Posted: Sat Aug 17, 2019 9:43 am
by PeterHeffron
Thanks. I think what I'll do is delete Vensim from the gaming computer, so I can use the flight simulator. I can then use Vensim on a secondary laptop that does not have the flight simulator.

It would be nice if there were an app that would enable one to assign 'virtual extension substitutes', such that several programs using the same file extension (e.g., '.mdl') could still run normally. For example, a .mdl flight sim extension could be virtually renamed '.mdl-fs' and a Vensim extension could be virtually renamed '.mdl-ven'... Then, theoretically, you could even run both programs at the same time. (Hey, you could work on a Vensim Model while on autopilot between Paris and New York; just taking a break from Vensim during takeoff and landing!)

Anyway, thanks again for the feedback and suggestions. -)

Re: vensim .mdl extension applied to flight sim files

Posted: Sat Aug 17, 2019 10:03 am
by Administrator
There really is no need to delete Vensim from the computer. All you need to do is use the shortcut to start it rather than double clicking on the model.