myPhysicsLab vs SimEvents

myPhysicsLab is a free, open-source project with interactive physics simulations and JavaScript classes for building animated models. Simulations run in real time, and users can drag objects or change parameters such as gravity. Its library includes examples such as pendulums, springs, colliding blocks, roller coasters, billiards, and molecular models. Many simulation pages explain the mathematics behind the models. Users can customize simulations with EasyScript or JavaScript in a browser and text editor, then share a setup through a URL that embeds EasyScript. Numeric results can be retrieved through VarsHistory, JavaScript, or collision-data scripts. Downloadable versions can be used offline. The source code is available on GitHub under the Apache 2.0 License. The simulations do not specify measurement units, so values need to be used consistently within each model. Building from source requires TypeScript, esbuild, Perl, and GNU Make. The project began in 2001, and its maker is based in Seattle, Washington.

SimEvents is desktop software for modeling message-based communication and other event-driven processes. It uses a discrete-event simulation engine and component library, and can combine event-based models with Simulink time-based models for large hybrid systems. Blocks represent entity creation and destruction, queues, service times, routing, attributes, and event responses. Resource Pool, Resource Acquirer, and Resource Releaser blocks model resource allocation, while repeated simulations can support optimization. Analysis includes latency, throughput, packet loss, queue lengths, delays, and average service times. Users can simulate and debug models, inspect queue contents, visualize entity activity, and build custom visualization tools. Output statistics aggregate measures, and Sequence Viewer displays messages, events, and entities. MATLAB Discrete Event System and Discrete Event Chart blocks allow custom behavior. Listed applications include communication networks, software and hardware architectures, forecasting, capacity planning, and supply chain management. SimEvents requires MATLAB and Simulink, runs on Windows, Mac, and Linux, and has a 30-day trial with paid licensing.