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Overview

The Veydra Live Bridge is a Google Workspace Add-on that connects Google Sheets directly to the Veydra System Dynamics Engine. It replaces static file exports with real-time, bi-directional sync — giving you native spreadsheet recalculation with sub-200ms latency.
Unlike legacy tools that require exporting .sem files and manually importing data, the Live Bridge maintains a persistent connection to your Veydra models with automatic updates.

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Key Benefits

Real-Time Sync

Changes in Sheets instantly update your Veydra model, and simulation results flow back automatically

Native Experience

Works with familiar spreadsheet features — formulas, ranges, and dynamic arrays

Multi-User Collaboration

Multiple users can work on the same sheet with real-time updates across all sessions

Live Model Info

Generate auto-updating sheets with all model variables, units, and current values

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How It Works

+----------------------------------------------+
|                Google Sheet                   |
|                                               |
|  +-------------+   +----------------------+  |
|  |  Sidebar UI |   |  =VEYDRA.FORECAST()  |  |
|  |  (Controls) |   |  Custom Functions    |  |
|  +------+------+   +----------+-----------+  |
|         |                     |              |
|  +------+---------------------+------------+ |
|  |         Apps Script Host Layer          | |
|  +--------------------+--------------------+ |
+------------------------|---------------------+
                         |  REST + WebSocket
                         v
           +------------------------+
           |   Veydra Cloud Engine  |
           +------------------------+
The Live Bridge consists of:
  1. Sidebar UI — A React-based panel for authentication, model selection, and parameter controls
  2. Custom Functions — Spreadsheet formulas like =VEYDRA.FORECAST() that fetch simulation results
  3. Apps Script Layer — Handles triggers, sheet I/O, and the WebSocket connection to Veydra

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Features

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Bi-Directional Cell Mapping

Map spreadsheet cells directly to Veydra model nodes: Sheet → Veydra (Inputs)
  1. Select a cell range in your spreadsheet
  2. Open the Veydra sidebar and click Bind
  3. Choose the input node to map (e.g., “Marketing Spend”)
  4. Changes to those cells automatically update the model
Veydra → Sheet (Outputs) Use the VEYDRA.FORECAST function to pull simulation results: 
=VEYDRA.FORECAST("model_id", "input_range", "output_node")
This function supports Dynamic Arrays — a 12-month forecast automatically populates 12 cells without needing to copy the formula down.

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Reactive Sliders

The sidebar includes interactive sliders for model parameters:
  • Drag a slider to change a parameter value
  • The Veydra engine recalculates immediately
  • Results update in your spreadsheet in real-time (no manual refresh)
This is perfect for sensitivity analysis and exploring “what-if” scenarios.

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Model Info Generator

Generate a comprehensive summary sheet of your connected model:
  1. Open the sidebar and click Generate Model Info Sheet
  2. A new sheet is created with all variables, their units, and current values
  3. Unlike static exports, this sheet stays synchronized with your model

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Multi-User Real-Time Sync

When multiple users have the same Google Sheet open:
  • User A changes a parameter via the sidebar
  • User B sees the updated values appear in their sheet automatically
  • Both users see the same simulation results
This enables collaborative scenario planning and teaching sessions.

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Getting Started

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Installation

1

Open Google Sheets

Create a new spreadsheet or open an existing one at sheets.google.com
2

Install the Add-on

Go to Extensions → Add-ons → Get add-ons and search for “Veydra Live Bridge”Click Install and grant the required permissions
3

Open the Sidebar

After installation, go to Extensions → Veydra Live-Bridge → Open Sidebar
4

Sign In

Click Sign in with Google in the sidebar to authenticate with your Veydra account

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Connecting a Model

1

Select a Model

In the sidebar, use the Model dropdown to select from your available Veydra models
2

View Model Details

Click Generate Model Info Sheet to see all available variables and their current values
3

Bind Input Cells

Select cells in your sheet, then click Bind in the sidebar to map them to model inputs
4

Add Output Formulas

Enter =VEYDRA.FORECAST() formulas to display simulation results

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Custom Functions Reference

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VEYDRA.FORECAST

Runs a simulation and returns the forecast values for an output variable. 
=VEYDRA.FORECAST(model_id, input_range, output_node, [periods])
ParameterTypeDescription
model_idStringThe Veydra model ID (found in the model URL)
input_rangeRangeCell range containing input values
output_nodeStringName of the output variable to return
periodsNumber(Optional) Number of time periods to forecast
Example: 
=VEYDRA.FORECAST("12345", B2:B13, "Revenue", 12)
Returns a 12-row array of forecasted revenue values based on the inputs in B2:B13.

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Comparison with Legacy Tools

FeatureStella/Vensim (Legacy)Veydra Live Bridge
Data syncStatic .sem file exportsLive WebSocket connection
Update latencyManual re-importUnder 200ms automatic
CollaborationSingle-user file ownershipMulti-user real-time sync
Info sheetsStatic snapshotLive-updated
Dynamic arraysNot supportedNative support
Version controlManual file copiesCloud-based with history

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Troubleshooting

  • Verify you’re signed in with the correct Veydra account
  • Check that you have at least one model created in Veydra
  • Try clicking the refresh button next to the model dropdown
  • Verify the model ID is correct (check the URL in app.veydra.io)
  • Ensure the output node name matches exactly (case-sensitive)
  • Check that your input range contains valid numeric values
  • Check your internet connection
  • The WebSocket connection may have timed out — close and reopen the sidebar
  • Verify the Veydra service is operational at status.veydra.io

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Requirements

  • Google account with access to Google Sheets
  • Veydra account with at least one model
  • Modern browser (Chrome, Firefox, Edge, or Safari)
  • Internet connection for real-time sync