This article applies to iGrafx Process and iGrafx Process for Six Sigma Client tools.
iGrafx provides various logical functions (If, Select, and Switch) that may be useful in controlling your decisions in a simulation model. In addition, the If function can be used either as an Else-If style syntax, or by nesting If functions within other If function calls.
In general, if you have 5 or fewer decision cases, any of the functions may provide useful to you, depending on your preferences for how to model. This limit is because the Select and Switch functions can take 12 or fewer parameters, and the case number or switch value and default take 2 of the parameters. So that leaves 10 parameters (arguments) to the function. In the Switch function, each decision case will take 2 parameters, so you have a total of 5 decision cases you may use. If you have more than 5 decision cases, then using either the Select function (for up to 10 decision cases), or the If function (either with ElseIf or nested If functions) is recommended.
The attached file has examples of using a user-defined 'Type' to limit possible values of an attribute (variable), and then using various methods-- including If, Select, and Switch-- to control a decision. There are notes in the shapes within the file that document each method.