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General FAQs

Where can I find my registration number?

You can find your registration number on the “My Products” page after you’ve signed into your isee systems account.

If Stella is installed, you can also find your registration number in the Stella software. On Windows, click on the Help menu and select About Stella, OR on Mac click on the Stella menu and select About Stella.

What is Systems Thinking?

Systems Thinking is a disciplined way of understanding dynamic relationships. It helps you make better choices and avoid unintended consequences. Learn more Here.

What is isee Player?

isee Player software allows you to open and interact with Stella models. While using isee Player, you can view the model diagram, run the model, and use Stella Live to interact with it by changing variables. Editing capabilities are restricted and the Interface window is not available in the isee Player.

Why is storytelling (Stella Architect/Stella Designer) such a powerful feature?

Storytelling is a feature unique to Stella Designer and Architect that allows you to present and explain your model piece-by-piece. Even more powerful is the ability to show the behavior as the structure of the model unfurls. Through storytelling, you can clearly create and communicate the link between the structure of the system and the dynamic behavior. For more details, read our Blog Post or our help page for stories.

How can I make my simulations run on the web?

Stella Architect allows you to build user interfaces for models and publish them to the web. (Stella Designer also has this capability but is meant for customers who are working closely with a model developer and don’t require the use of Stella Architect’s model creation functionality.)

Can I customize the way my user interfaces look on the web?

Yes, Stella Architect has robust interface creation tools that include Templates, Story Telling, Animations, video, graphics and navigation. All of these features are supported once the model is published to the isee Exchange. However, if you would like to add your own unique look and feel to your simulation, you can use the Stella Designer Developer Kit. Contact for more information.

How can I integrate my model with other applications?

If you want to link data to your model, you can set up dynamic data import/export links to Microsoft Excel or .csv files.

If you want to integrate your model with other applications, in some cases, you can use the command line.

Is there any online help documentation for Stella Architect?

Help documentation can be found here. Or, within Stella, click on the Help menu and select Online Help.

How do I access Stella Online if I don’t own Stella Professional or Stella Architect?

We offer a free, limited functionality version of Stella Online to anyone with an isee Exchange account. If you don’t have an Exchange account, you can create one at The Free Stella Online includes the use of up to three stocks, twenty entities (including stocks), one graph, etc. Go to Stella Online to learn more about the Free Stella Online and other options.

How can my university students run Stella on their computers?

We have several student licensing options. You can view them on our Education webpage.

When you upload a model (as opposed to a simulation) to the Exchange, is it available to everyone?

Yes, the models are licensed under this version of the Creative Commons license: However, if you have a Stella Professional or Stella Architect license, you can use an All Rights Reserved license to keep your model private.

Can I open a Stella Professional model in Stella Architect and vice versa?

Yes. However, Stella Professional does not include the Interface Window, so you won’t be able to access the interface of a Stella Architect model opened in Stella Professional.

What’s the difference between Stella Architect and Stella Professional?

Stella Architect is our flagship product that includes modeling and simulation functionality, interface creation, and the ability to publish models to the web. Stella Professional only has modeling and simulation functionality. Models built in both can be uploaded to Stella Online.

What’s the difference between iThink 10.1.2 and Stella Architect?

iThink/STELLA 10.1.2 is the last version of our older software. In 2015, we completely rebuilt our software with current development tools to replace 10.1.2 as it was becoming outdated. Stella Architect and Stella Professional are the new versions of our software. (See the above question for the difference between Architect and Professional.)

How do I access Stella Online if I own Stella Professional or Stella Architect (with a non-student license)?

To gain access to the full version of Stella Online, you must link your isee systems account to your isee Exchange account by following these steps:

  1. If you haven’t already, create an Exchange account at
  2. Log into your isee systems account at
  3. Go to the “My Account” menu, select “My Profile”, and scroll down until you see the link that reads, "click to provide your isee Exchange account credentials or to create a new isee Exchange account."
  4. Click that link and and enter your Exchange account credentials.
  5. Select “Link My Accounts.”

You can now access the full version of Stella Online as long as you have active support.

Can I open a Stella Architect or Stella Professional model in iThink/Stella 10.1.2?

Since we used the latest development tools to build Stella Architect and Stella Professional, models created or saved in these applications are not compatible with older software (iThink and Stella 10.1 or earlier).

How do I access my published simulations and online models?

You can access your published simulations by logging into your Exchange account and selecting the Sims option in the top menu. Your online models will be found under the Models menu.

When you publish a simulation to the isee Exchange, is it available to everyone?

Anyone who visits the Exchange may find your published simulation by using the search tool or through a link to your simulation. Authors who publish sims to the isee Exchange agree to this version of the Creative Commons license: However, isee systems offers additional authentication services for users who want to publish models privately. If you are interested in these services, please contact

On the isee Exchange, what is the difference between Sims, Models and CLDs?

Sims are created by publishing the Interface of your model from Stella Architect. Sims show a model’s interface and allow you to change variables using input devices that the model author added to the interface, run the simulation over time, and view results. There may also be animations, stories, or other interface objects that help the end user learn more about the system.

Models on the isee Exchange are created by building one in Stella Online or uploading models made in the desktop version of Stella. If you created or uploaded the model, you can continue to edit and run the model online. You can also share the model by sending the link to others. When others open your model, they can run it in the Stella Online Player, save it as a copy, and make changes to it.

CLDs on the isee Exchange are Causal Loop Diagrams that can be created with the Stella Online CLD Editor or uploaded from your computer and used just like uploaded models.

Where can I find the Stella Online Model and CLD Editors?

The Online Model CLD Editors are available on the isee Exchange. To access the Exchange, go to and log in with your isee Exchange password (or create an account if don’t have one). Please note that isee Exchange accounts are different than user account on Once you’re signed in, you'll see one tab called CLDs that will take you to the CLD Editor and another called Models that will take you to the Model Editor.

What's the difference between Stella and iThink?

iThink is a rebranding of Stella Architect for those who are more familiar with the iThink brand. It is functionally identical to Stella Architect. Before the introduction of the iThink brand in 1990, this product was called STELLA for Business.

Can I open iThink models using Stella and vice versa?

Yes, whether you are using Stella or iThink, you can open both Stella models (.stmx files) and iThink models (.itmx files).

Looking for software help?

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