I need help (venapp)

almoon · Post by **almoon** » Mon May 10, 2010 10:03 pm

I finished my model but am planning to build an interface using venapp but my problem am very confused how can I start ?
the more I read in Vensim documentation the more I get confused

I really need help

Post by **tomfid** » Mon May 10, 2010 11:45 pm

One good way to start is to try the various venapp interfaces included in the sample models, find one you like, and start modifying it. It's generally easier to proceed incrementally from something that's working.

Another possibility, if you're more comfortable with C, Java, Visual Basic, etc., is to work in Excel or a programming language, using the Vensim .dll.

To support simple experimentation with a model, you don't really need to build a Venapp; you can do a lot with the on-screen Input Output Objects and synthesim mode, even in Vensim PLE.

What do you want users to do with your interface?

Tom

almoon · Post by **almoon** » Tue May 11, 2010 11:43 am

Tom,
Many thanks for your help,I built with vensim a university management process but am planning to do an interface for the staff, it is a part of my phd project, am not good at any programming language..
so what is ur recommendation for me ?

almoon · Post by **almoon** » Tue May 11, 2010 12:05 pm

Also how can I open the examples from the sample it is not working

almoon · Post by **almoon** » Tue May 11, 2010 12:23 pm

when I press it, it said chose a program to open with so what shall I choose?

Post by **tomfid** » Tue May 11, 2010 3:18 pm

Start Vensim, and choose File>Open Model...

Change the file type to "Vensim Application Definitions"

Navigate to the sample models (normally in the directory where Vensim is installed), e.g. C:\Program Files\Vensim\models\sample

Open Intro.vcd, which is a portal to a variety of sample model interfaces.

When you find a demo you like, make a copy and work from that. I'd recommend something as simple as possible. The synthesim demo, for example, is entirely contained in one screen (DEMO9X in Intro.vcd).

Is this an interface for staff to use on their own, or to be demonstrated by an experienced modeler? Will there be one or two users who can be trained, or many? Do they need to make and archive multiple runs, or just play with the model to get a feel for it?

almoon · Post by **almoon** » Tue May 11, 2010 10:24 pm

Tom, you are the best

I spent 2 days try to work on it, and now you give it to me in 5 min

yes it is for staff to use on their own, with multiple interfaces, no need to archive multiple run I guess.....

Any recommendation ?

almoon · Post by **almoon** » Wed May 12, 2010 8:08 pm

Tom, sorry to bother you but how can I make as copy as u mentioned before and start work on it ? can you explain that to me if you don t mind

Post by **tomfid** » Wed May 12, 2010 8:34 pm

Venapps are in .vcd files, which are just plain text. You can edit them inside Vensim via File>Edit File ... which has the huge advantage of permitting you to switch to sketch view (View>As Sketch) to check/edit the placement of on-screen graphs, buttons, etc. Use the buttons and menu in the bottom toolbar to navigate and preview single screens. Use the File>Run Venapp or the corresponding button to test your app.

If you have a .vcd that you like, open it with File>Edit, then use Save As ... to create a fresh copy. I recommend putting the model, .vcd, and any other needed files in a single project directory. My habit is to save the .vcd with a new version number ("myApp21.vcd") from time to time, and to make a fresh copy of the folder once in a while, deleting any obsolete stuff. That way you have backups, and don't get too confused about the active file.

For a few purposes, like extensive search & replace, it's easier to use an external text editor. I recomment Notepad++ (free, open source).

Tom

almoon · Post by **almoon** » Fri May 14, 2010 8:13 pm

Tom, Many thanks for your help.

I started to work on it yesterday and it was working, but suddenly something wrong happen as I start receiving this message, when I open it from edit file and then run Venapp I got the following :

( Unable to open intro.vmf to read model) if I press OK another message come (unable to read intro.vmp).

then (bad sketch number 6) then (unable to open to read intro user graphs).

So what is going on

Post by **tomfid** » Fri May 14, 2010 8:50 pm

Not sure exactly. Is everything in the same folder? The direct cause of the message is that Vensim is unable to open the model in your specified location.

Tom

almoon · Post by **almoon** » Fri May 14, 2010 9:25 pm

I thought so, because I moved the folder to the desktop to make it easy for me to open it, then I tried to return it to its location but it didn't work, so I tried to download the models and example only from the vensim website but when it downloaded it gives a message to choose a programs to open with so what should I do ?

Post by **tomfid** » Fri May 14, 2010 10:23 pm

Do you still have the original models folder? If not, you can restore it by reinstalling Vensim (I'm guessing that what you downloaded is one of the installer archives, which won't work by itself). When you reinstall, be sure that the option to reset the .ini settings is unchecked, if you want to save any options you've customized.

The sample models should work in any "normal" location. I'd recommend making a copy of what you found in the Vensim directory and storing it in a separate location (on windows, in a directory in My Documents is convenient).

almoon · Post by **almoon** » Thu May 20, 2010 1:52 pm

Many thanks Tom

its work