If you have a COMSOL Multiphysics® installation you can launch apps from the Revit® user interface by clicking the Run Application () button on the COMSOL Multiphysics tab in Revit®. In the Open dialog browse to the application, then click Open. This will bring up the app interface in a separate window. If the application utilizes the LiveLink™ interface make sure that the CAD document is open in Revit® before using the app.

Note that the Run Application button is disabled if you have a COMSOL Client installation of LiveLink™ for Revit®. In this case run the app with the COMSOL Client, for example by first logging in to a COMSOL Server interface as described in the section Connecting to a COMSOL Server™.