【正文】 t will be represented by default geometry contained in a part file in the library defined by the current value of DEFAULT$LIB directory. The system is shipped with default geometries. These may be customized as desired by renaming the your CAD part to that of the default geometry. Select from libraryYou are prompted to select a file.2D IconsThe 2D world is a schematic representation of the 3D world. The 2D environment gives you the flexibility to view run time data in a dynamic way, which will be updated during a simulation run. The model in the 2D world is an iconic representation of the 3D model. The charts and icons associated with a particular element of the model represent that element. The following buttons allow you to assign an icon to a 3D element, that will then be used to represent that element when it is put into the 2D world with the Model | Build | Element | Populate button:No. of IconsThe number of icons that are assigned to the element.Icon FileThis button is used to define the Icon file:Icon IndexThe Icon index defines the geometry index for an Icon. The index ranges from 1 to No. Of Icons assigned earlier. FileYou can assign either the Default Geometry File from the DEFAULT$LIB directory or select a library file from the ICON$LIB directory.The 2D world is covered in more detail in Chapter 7, Model Output and 2D Modeling. No. of Labor Points This button is used to set the number of labor points for an element. Labor points are similar to stack points except they are used to set the location of laborers when present at an element. Load and Unload Processes This button sets the manner in which parts are to be loaded into or unloaded from the element. The default is that parts can be loaded and unloaded without any time or resources being required. Very often the operation of an element receiving or sending a part needs to be modeled in more detail. It may be that there is simply a time delay between the part arriving at a element and actually being loaded on to it. In other cases more detail may be required, such as particular resources like a labor or a forklift may be needed to perform the load or unload operation. An element in QUEST can handle these situations by assigning a load process or unload process. These buttons present you with three alternatives for loading and unloading. None This is the default and specifies that no load process is used.Time Only Time only allows the specification of a time delay for loading parts. Selection of this option brings up the Distributions dialog box. This dialog box allows two distinct types of unload time:Deterministic, using the constant or file based selections, or Stochastic (random), using a probability distribution from the list.In addition, you can write an SCL routine that produces the load time using User Func. When a file based load time is chosen you are prompted to supply the location and name of the file containing the load time data. The data file must be in a SCHEDULE$LIB directory. In this way a model can be run using data from the real world either to improve the accuracy of the simulation or perhaps as part of the model validation process. New Process New Process allows a process to be associated with the loading/unloading. This may be either a new process or one that has already been defined. Processes are covered in more detail in Chapter 4, Logical Modeling Elements. The definition or association of a process here allows loading or unloading to require certain part binations and additional resources and to specify the duration. User Attributes This button is used to define a user attribute. The attribute can be of numeric (that is, of type real) or string type. The user attributes, which are created at the class level with some default values, can be modified at the element level to assign specific and different values for each element of the class. Selecting the User Attribute button will give a User Attributes dialog box.AddThis is used to create a new user attribute. A dialog box will be displayed asking for a name and type (either numeric or string). By default, user attributes, when created, are assigned a value of zero or null. ModifyOnce created, a user attribute may be assigned a value using this button. It may also be used to modify an existing value or user attribute name. After selecting the name of the user attribute to modify, the name or the numeric value or string value can be modified.NOTE: The type of the user attribute cannot be modified through this feature. The only way to modify the type is to delete the user attribute and create it again.Delete This is used to delete a user attribute. On selecting a user attribute and on confirmation it will be deleted. NOTE: By deleting the user attribute at the element class, it will be deleted from all the elements belonging to that class as well.Saving Individual Elements The Save In pull down menu allows you to save the element to be created as either part of the model file or in an independent file in the ECLASS$LIB directory. This button is useful for saving element classes so that they may be reused in later models, thus saving time in redefining new element classes. Saved classes can be recalled by using File | Read Entity and selecting Element Class.Displaying an Element’s Properties The Properties button displays a summary of the current settings for the element class. Components of a Labor System Labor modeling involves multiple elements working together. The elements involved are:Laborers Labor controller (referred to as controller or global controller ) Labor decision points (referred to as decision point or local controller) Labor path system (referred to as path system) Labor points Labor Via pathsThe labor path system and labor decision points are only used when modeling labor o