Ventana software support forum

Dear Sir,

I am developing a C++ project to show and represent Vensim simulation results. I do not need to simulate from this program just to represent results. I am using vensim dll like vdpdll32.dll.

My first problem is that I need to represent results from different versions of vensim program simulation : 5.4d and 5.7. I have both vdpdll32.dll and I have saved in different directories. From within the code I select such dll in order to load vdpdll32.dll from the directory of the version I need.

I have not installed vensim on the PC where I am going to use my program. Just I have copied the two dlls.

Everything it seems to go well with 5.4d dll but when I load 5.7 dll instead I have the "reinstall vensim" error when it executes "vensim_command"

How can I solve this?

Thank you,
Jose Fornes

Hi Jose,

You need to install Vensim on the computer you are doing development with. The Vensim DLL is part of Vensim DSS and can't be copied to another location.

Ok,

but if I install 5.7 vensim version after 5.4d version on the same computer, the new dll overwrites the old dll because it has the same name on windows\system32.

Is there any posibility to chose between two vensim versions installed on the same computer?

Thank you,
Jose Fornes

Why don't you just use 5.7 (better yet 5.8c)? - what is it that does not work in this version?

I am changing the code of a previous project and there are some diferencies:
1) The way Vensim is registered into the windows registry is different from Vensim versions and knowing if Vensim is installed on the system changes from the code.
2) My first application simulates scenarios and it opens .vmf files (this is posible with 5.4d dll). When I have 5.7 installed, it works only with .vpm files (5.7 dll does not work with .vmf files). So it depends on vensim version to open the model. Now I have errors when I start my applications if I have 5.7 installed. I know I can convert the model to .vpm but I am trying to avoid changes to our first users. When I open a .vmf file with 5.7 dll, it seems it works but vensim help tells that vensim 5.7 dll only works with .vpm files.
3)I would like to build a robust application, that it permits to work with a model with the same vensim version it was developed and simulated.
4) I am not an expert in Vensim but users tell me about changes with global variables in vensim versions
5) We are now using the new performances of 5.7 version like scenarios but I can not represent results of previous .vmf simulated files

The new way that Vensim works is very much like the way Adobe Acrobat works. User's develop the model anyway they want. When they are happy the simply publish it and include all the supporting files. This published model is then guaranteed to be the same as the model they were working with, and to include all the necessary supporting files. This is far more robust then trying to use just the model file, which might be changed, and hoping the correct supporting files are included..