Skip to main content

​
Overview

The Model Playground is Veydra’s central workspace where you build, modify, and test your system dynamics models. It provides an interactive environment with real-time feedback and powerful visualization tools.

​
Key Components

The Model Playground consists of several integrated panels that work together:

Model Controls

Parameter adjustment and simulation controls

Stock-Flow Diagram

Visual representation of your model structure

Chart Area

Real-time simulation results and comparisons

Code Editor

Direct Python code editing and customization

​
Model Controls Panel

​
Parameter Management

The Model Controls panel is your command center for model interaction:
  • Active Parameters: Parameters available for real-time adjustment
  • Parameter Sliders: Interactive controls for each parameter
  • Reset Functions: Quickly return to default values
  • Scenario Management: Save and load different parameter sets

​
Control Features

Mark parameters as “Active” to enable real-time slider controls during simulation
Use the refresh button to reset all parameters to defaults while keeping them active for quick experimentation
Enable “Compare Mode” to see baseline vs current scenario side-by-side

​
Stock-Flow Diagram Area

​
Visual Model Building

The diagram area provides an interactive view of your model’s structure:
  • Stock Elements: Rectangular boxes representing accumulations
  • Flow Elements: Arrows showing rates of change
  • Connectors: Links showing influence relationships
  • Parameters: Variable elements that can be adjusted

​
Interactive Features

  • Drag and Drop: Reposition elements for better layout
  • Real-time Updates: See value changes during simulation
  • Zoom and Pan: Navigate large, complex models
  • Element Properties: Click to edit element details
The diagram automatically updates to reflect changes made in the code editor

​
Chart Area

​
Visualization Options

Single Stock View

Focus on individual model components

Multi-Stock View

Display all stocks simultaneously

Comparison Mode

Baseline vs scenario analysis

Data Export

Export simulation results

​
Chart Features

  • Interactive Legends: Show/hide data series
  • Zoom and Pan: Explore different time ranges
  • Tooltips: Detailed value information on hover
  • Time Units: Automatic scaling (days, weeks, months, years)

​
Code Editor

​
Python-Based Models

Veydra uses Python for model execution, giving you full flexibility: 
# Example model structure
def model_function(parameters):
    # Define stocks and flows
    population = parameters['initial_population']
    growth_rate = parameters['growth_rate']
    
    # Calculate changes
    new_population = population * (1 + growth_rate)
    
    return {
        'population': new_population,
        'growth': new_population - population
    }

​
Editor Features

  • Syntax Highlighting: Python code formatting
  • Auto-completion: Intelligent code suggestions
  • Error Detection: Real-time syntax checking
  • Version Control: Git integration for change tracking

​
Simulation Engine

​
Real-Time Execution

The simulation engine processes your models using:
  • Pyodide Integration: Python execution in the browser
  • WebAssembly: High-performance computation
  • Incremental Updates: Fast parameter changes
  • Memory Management: Efficient data handling

​
Performance Features

  • Caching: Smart caching of model files and configurations
  • Parallel Processing: Multiple scenario execution
  • Optimization: Automatic performance tuning
  • Error Handling: Graceful failure recovery

​
Workflow Example

1

Model Setup

  1. Load or create a new model
  2. Review the stock-flow diagram
  3. Identify key parameters to activate
2

Parameter Configuration

  1. Mark important parameters as “Active”
  2. Set initial values using sliders
  3. Configure simulation time range
3

Simulation

  1. Run initial baseline simulation
  2. Adjust parameters in real-time
  3. Compare different scenarios
4

Analysis

  1. Review chart results
  2. Export data for further analysis
  3. Save interesting scenarios

​
Advanced Features

​
Git Integration

  • Version Control: Track all model changes
  • Branching: Experiment with different approaches
  • Merging: Collaborate on model development
  • History: Review past versions and changes

​
Collaboration Tools

  • Real-time Sharing: Multiple users in same playground
  • Comments: Annotate models and results
  • Permissions: Control who can edit vs view
  • Change Notifications: Track team member activities
Use the Model Playground’s reset functionality to quickly experiment with different parameter combinations while maintaining your baseline for comparison

​
Next Steps

Simulation Features

Learn about advanced simulation capabilities

Model Controls Guide

Detailed guide to parameter management
⌘I