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Technical Guide - Version 2.0

isee NetSim™ is a utility that allows you to publish your iThink and STELLA models to the Internet. Publishing models to the web makes it easy to share your models with anyone, even if they don’t have iThink or STELLA. All they need is a browser with Adobe Flash Player 9 support and a connection to the location where you will publish the models (either an Internet connection, or a connection to a Web server that is running the isee NetSim Server software).

To publish models with isee NetSim, you must do the following:

  1. Prepare the model Interface by laying it out in pages.
  2. Check the model meets isee NetSim requirements and does not include unsupported interface objects.
  3. Export the model from iThink or STELLA as a NetSim (*.TXM) file.
  4. Use the isee NetSim wizard to publish the model to the location you select.
Preparing the Model Interface

The first step to preparing your model for isee NetSim is to carefully lay out the Interface layer of your model so that the page size is appropriate for your viewers and all of the interface objects fit inside those pages.

If you are building a model from scratch you should plan the lay out of the Interface layer as you build the model. If you are publishing an existing model, you may need to make some minor changes to the layout to be sure that objects appear correctly on pages before you export or publish the file.

To lay out interface pages

  1. In iThink or STELLA, open the model whose pages you want to publish.
  2. Go to the Interface layer.
  3. From the Interface menu, choose Interface Prefs. The Interface Level Preferences dialog box opens.

Interface Level Preferences

  1. To enable pages on the Interface layer, select the Show Pages check box.
  2. Use the Width and Height boxes to specify the size of the Interface layer in pages. For example, to have the Interface layer be divided into just two pages across, type 2 in the Width box and 1 in the Height box. The Total Pages value updates to indicate the total number of pages you've specified.
  3. Click the Page Size button. The Page Size and Runtime Options dialog box opens

Page Size and Runtime Options

  1. Select the appropriate Page Size option. This option determines how the pages will be formatted based on the screen resolution you select. In general, we recommend that you select the 800 x 600 option, unless you are sure all of your model viewers will be using a different screen resolution.

    Note:  Selecting Other allows you to enter a custom page size. By default, Other will be the same size as your printer settings.

  2. Use the Home Page box to specify which page is the starting page when users view your published model. The Home Page is also the page that users will be navigated to if you include a Home button on the Interface.
  3. Click OK.

The Interface layer now shows dashed lines that indicate the boundaries of the pages you specified.


  1. Create and/or arrange interface objects on the pages. When you define navigation buttons, you can use the previous page, next page, and home page options to navigate between pages.

Tip: To easily move many objects at once, zoom out on the model and then use drag-select to select multiple objects at once, then drag one selected object to move them all the same direction and distance.

isee NetSim Requirements

To publish a model with NetSim, the model must be able to be run. If not, you will see an error message when you try to export the model.

If your model contains interface objects that are not yet supported by NetSim, the export will not fail, but you will receive a message during publication that lets you know the objects have been excluded from the model.

Below is a current list of unsupported interface objects:

  • Scatter and Sketchable Graphs
  • Tracing Buttons
  • Loop Pads
  • Sectors and Sensi on/off switches
  • High level mapping tools including Process Frames and
    Bundled Flows and Connectors

Note:  Some interface objects have options in STELLA and iThink that either don’t make sense for the web or aren’t yet supported by isee NetSim. The following table lists the options that are not currently available on the web:

Interface Object Options not yet supported
Navigation Button
  • Visual effects
  • Password Protect
  • Post a Message
  • Switch Module On or Off
Menu Button
  • All except Run, Pause, Stop, Resume,
    Run/Restore, Restore All Devices, Restore Graphs & Tables, Print, and Print Screen
Hyperlink Button
  • Local file
Graphical Input Device
  • Show navigation arrow
  • Ability to edit the range of values on the x and y axis
  • Editable data columns
List Input Device
  • Show navigation arrow
  • Format Options
  • Show navigation arrow
Graph Pad
  • Show numbers on plots
  • Hide detail
  • Mark for export
Table Pad
  • Hide detail
  • Mark for export
  • Header Style
  • Header Justify
Status Indicator
  • Panic sound
Numeric Display
  • Show navigation arrow
Text Box
  • Wide margins
  • Mark for export
Exporting Models for Publication

To publish models with isee NetSim, you need to export the model from iThink or STELLA as a NetSim (.TXM) file

To export a model file for publication

  1. Open the model file that you want to publish in iThink or STELLA.
  2. From the File menu, choose Export for NetSim. The Save NetSim file as dialog box opens.
  3. Navigate to the location where you want to save the file.
  4. In the File name box, type the name you want to give the file (by default, the name is the same as the model file’s name).
  5. In the Save as type box, make sure that NetSim file (*.TXM) is selected.
  6. Click Save.
  7. You can now publish the TXM file with isee NetSim.
Publishing Models with isee NetSim
  1. Start isee NetSim by double-clicking the Netsimicon on your desktop. The first page of the wizard opens.

    isee Netsim Wizard

    This page provides an introduction to the process and reminds you that you need to first export your model in order to publish it with isee NetSim.
    Note: You can hide this page in the future by selecting the Skip this page next time check box.
  1. Click Next. The second page of the wizard appears.

isee Netsim Wizard 2

  1. Click the Browse button at the top of the page to navigate to and select the .TXM file that you want to publish.
  2. Under “Where will the model be published?”, select where you want to publish the model:
    • To publish the model to Forio Simulate, select Forio Simulate web simulation hosting service. Forio Simulate provides free hosting for iThink and STELLA models with up to 400 equations. For more information about Forio Simulate hosting options, visit
    • To publish the model to any other web site, select Other service: and then type the full URL of the web site where you want to publish the model.

Note: If your Internet connection goes through a proxy server, see configuring isee NetSim for Internet proxy server connections.

  1. In the next section type your email address and the password for the location where you want to publish the model. If you do not yet have an account, click the Don't have an account? link to create an account by providing your name, email address, and a password.

    Note: If you have already created an account but have forgotten your password, click the Forgot your password? link. You will be prompted to enter your email address so that your password can be emailed to you.

  2. To save your login information for the future, select the Remember me check box.
  3. Note: If you have already published one or more models, you can see a list of your published models by clicking the View or delete my published models link. A web page appears that displays a list of your published models. Use this page to view or delete your published models.

  4. Click Next. The third page of the wizard appears.

  5. Under "Publishing Mode", select who can see the published model:
    • To publish the model to a temporary location that only you can access, select Preview.
    • To publish and save the model to a location where it can be shared with others, select Publish. If you would like others to be able to download the model file, click the Browse button to navigate to and select the model (.STMX or .ITMX) file.
  6. If you have defined one or more dynamic export links in your model and you have written a custom web service program to collect the exported data, you can select the Enable dynamic data export check box to enable this functionality for the model you are publishing.

    Note: This option is available only if you are publishing a model file that contains dynamic export links.

    If you select this check box, use the Web service endpoint box to specify the full URL of the web service program. The URL is the web page (resource) that will process the data and either store it in a database or write it to a file for a later viewing.

    Notes: The web service you specify here must be one that responds to an HTTP POST that contains model simulation data in JSON format. For more information about how to set up the web service endpoint, see Dynamic Export Service.

    If you have multiple dynamic data export links in the model, only the first one will be used by isee NetSim to export data.
  7. Click Next. The next page of the wizard appears, which displays the status of the publication process. isee NetSim logs in to the specified site and publishes the model. Once isee NetSim has finished publishing the model, the simulation automatically launches in your browser.
  8. When you are finished publishing models with isee NetSim, click Exit in the wizard.
Configuring isee NetSim for Internet Proxy Server Connections

To configure your isee NetSim installation to connect through a proxy server:

  1. Navigate to the directory where isee NetSim is installed. For Windows, the default installation directory is C:\Program Files\isee systems\isee NetSim 1.1
  2. Create a copy of the file named netsim.ini and rename it oldnetsim.ini
  3. Open the file named netsim.ini.
  4. Locate the line in the file containing Proxy URL::
  5. Enter the host name or IP address of the proxy server. For example,

    Proxy OR

    Proxy URL::

  6. By default, isee NetSim will connect to port 1080. To specify a different port number, enter a colon followed by the port number after the host name or IP address. For example,

    Proxy OR

    Proxy URL::

  7. Go to the File menu and select Save to save your changes to the netsim.ini configuration file.

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