model.variable(<tag>) returns a variable collection. Each variable collection can contain several variables, but only one selection.

 model.variable().create(<tag>) creates a variables node with tag <tag>.

 model.variable(<tag>).set(<var>,<expr>) defines the variable <var> by the expression <expr>.

 model.variable(<tag>).set(<var>,<expr>,<descr>) defines a variable and gives it a description.

 model.variable(<tag>).descr(<var>,<descr>) defines a description for the variable <var>.

model.variable(<tag>).model(<mtag>) sets the model component node.

model.variable(<tag>).selection().named(<seltag>) assigns the variable node to the named selection <seltag>.
model.shape(<tag>).selection().set(...) defines a local selection that assigns the variable collection to geometric entities. Before assigning a selection, the variable’s model must be set using model.variable(<tag>).model(<mtag>). Only the global selection and selections on a geometry in the model can be used. For a complete list of methods available under selection(), see Selections.

model.variable(<tag>).remove(<var>) removes a variable from the variable collection. model.variable(<tag>).clear() removes all variables from the variable collection.

 model.variable(<tag>).varnames() returns the names of all expressions as a string array.

 model.variable(<tag>).get(<var>) returns the variable value as a string.

 model.variable(<tag>).descr(<var>) returns the variable description as a string.

model.variable(<tag>).model() returns the model component node tag.

model.variable(<tag>).scope() returns the fully qualified scope name.

 model.variable(<tag>).selection().named() returns the selection tag as a string.

 model.variable(<tag>).selection().getType() returns domain information. For available methods, see model.selection().

For model.param().loadFile() and model.param().saveFile(), see The loadFile and saveFile Methods.

Define the expression e as x+1 in Domains 1 and 2 and as x-1 in Domain 3.