Backward Compatibility with Version 6.0
New CefSharp Browser
The Chromium™-based CefSharp browser component replaces the Internet Explorer-based .NET WebBrowser component in version 6.1.
In the Video and Web Page form objects, there is now a Native browser on Windows option in the settings to determine if the Internet Explorer®-based .NET WebBrowser component from earlier versions should be used instead. The default value for the native browser is Chromium™ (CEF) but all existing models have the setting set to Internet Explorer® by default to maintain the functionality from earlier versions. Use the launcher flag cs.legacywebbrowser=true as a way to keep the previous browser component instead of CefSharp.
The CefSharp browser component stores user data such as cookies, browser history, and local storage in a folder. This cscefcache folder is placed among the temporary files of the client and persist between COMSOL and browser sessions. You can delete the cscefcache folder to clear this data. The CEF log output is written to Users\[user]\.comsol\6.1\logs\cef.log. The log level can be controlled using the cs.cefloglevel launcher argument, which accepts the values info, warning, error, and fatal.
Equation Form for PDE and ODE Interfaces
When adding a PDE or ODE interface in the user interface, the equation form will by default be set to Study controlled. This will lead to a different interpretation of time derivatives in frequency-domain studies compared to previous versions. When creating a new PDE or ODE interface from the API or opening a model saved in a previous version, the equation form will be set to Time domain, which corresponds to the behavior in previous versions.
The Flash Movie Format
For movie export, the Flash format is no longer available as of version 6.1.
Time-Explicit Solver
The Time-Dependent Solver node settings now includes the time-explicit methods from the Time-Explicit Solver node that was available in the Model Builder in earlier versions. The Time-Explicit Solver node is still available in models created in earlier version of COMSOL Multiphysics. It is also available in the COMSOL API.
Model Reduction Study Step
The Study step for eigenmodes and Study step for constraint modes settings in version 6.1 correspond to Defined by study step in previous versions because it is not possible to use one study step for two different solution types.
Periodic Conditions — Destination Selection
The Destination Selection subnode under Periodic Condition nodes has been removed in version 6.1 and has been replaced by an optional Destination Selection section in the Settings windows for Periodic Condition nodes. It can still be added from the API for backward compatibility. The Destination Selection subnode was used for two purposes:
For more information about the API compatibility, see COMSOL 6.1 API Changes.
Flash Movie Format
The Flash movie format is no longer available for export of movie files using the Animation feature. Animation features in models created using version 6.0 or earlier where the format is set to Flash now use GIF as the format in version 6.1.
Streamline Plot Changes
For 2D Streamline and 3D Streamline Surface and Streamline Multislice plots, the algorithm for finding and plotting streamlines has been improved. The Density setting in version 6.0 and earlier versions has been replaced with the Maximum distance setting, which is the inverse of the Density. A corresponding Minimum distance setting has also been added. When opening models from version 6.0 and earlier versions, the Minimum distance is assigned a value that is 0.05 times the Maximum distance. This is a reasonable heuristic, but it is not guaranteed to give a good result in all cases.
Physics Symbols in 1D and 0D Geometries
The Physics Symbols section in the settings for physics interfaces, features, and boundary conditions has been removed for all components with dimension less than 2D. This change might cause issues with old public API code that accesses any physics symbol properties in 1D or 0D, even though they did not have any effect in earlier versions either.