The General Form PDE (g) interface (), found under the Mathematics>PDE Interfaces branch () when adding an interface, is a flexible way to specify PDEs in a general form.

When this interface is added, these default nodes are also added to the Model Builder: General Form PDE, Zero Flux, and Initial Values. Then, from the Physics toolbar, add other nodes that implement, for example, boundary conditions. You can also right-click General Form PDE to select features from the context menu.

The Label is the default physics interface name.

The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.

The default Name (for the first General Form PDE interface in the model) is g (in domains), gb (on boundaries), ge (on edges), or gp (at points).