Backward Compatibility with Version 5.1

Creating Selections

In version 5.2, the selresult property replaced the createselection property. createselection is still supported for backward compatibility.

Selections in Part Instances

For backward compatibility for selections in part instances, there is a Keep noncontributing selections check box, cleared by default, in the Selection Settings section of the Settings window for Part Instance nodes. If you select the Keep noncontributing selections check box, the Keep column is disabled, and the selection is kept if the Contribute to value is None. In the COMSOL API, the default is an active Keep noncontributing selections setting.

Mesh Parts

For backward compatibility regarding STL/VRML import, and for COMSOL API compatibility, the old user interface for mesh import (with a specified file name and import properties) and the corresponding properties are available in the COMSOL API but not in the COMSOL Desktop, unless it is the active option. This means that the old user interface can only be reached if the filename is set in combination with the STL import type (the API type stlvrml), which cannot be done from the new user interface.

Dormand-Prince 5 Time-Stepping Solver

The Dormand-Prince 5 Runge-Kutta solver in 5.1 does not use field norm scaling in version 5.1 when estimating errors. This means that the errors of, for instance, an ODE might become very small when solved together with a field with many DOFs, and the time steps taken might then be too large. In version 5.2a, the Runge-Kutta solver uses field norm scaling, which means that old models using the Dormand-Prince 5 might need tighter tolerances to produce results in earlier versions that are similar to those in 5.2a.