For the definition of primitive parameters you have to use the Property Editor.
As for any hierarchical module, you can create additional properties that define model parameters. Use the menu item New Parameter in the context menu of the Property Editor to create a new parameter.
The parameter is created with default values for all parameter elements. You can define the following elements:
For detailed information on the type and significance of parameter elements you may refer to the Primitive Language Constructs section. For each defined parameter MLDesigner generates on saving a defparameter item in the primitive source file. These items cannot be changed in the primitive source file; they must be changed using the parameter properties of the primitive interface model.