A parameter template consists of three types of data units: selection types, functions and parameters. Descriptions of the three follow.
Selection types are part of selection parameters and define the strict set of values that these parameters can have.
Selection types are made up of selection type entries, which are concrete values that you can select and set to a selection parameter. A selection type entry is defined by a name (description), expression (value), and description. The selection type entry name (!!) is the value that a selection parameter has at any given time.
The picture below shows what a selection parameter looks like as made up of selection types and selection type entries.
In the following picture, the selection parameter Edge Modification can accept the predefined values Flat, Chamfer and LineExt.
When we create a resizable structure, we can create a selection parameter (EdgeType) that uses the predefined selection group Edge Modification. EdgeType will then take part in the expression of DFC1, the parameter that controls the structure's contour:
The expression of DFC1 uses a function whose argument is the selection parameter EdgeType. So when EdgeType has the value:
| EdgeType Value | Returns |
|---|---|
| Flat | 0 |
| Chamfer | The thickness of the material. |
| LineExt | The thickness of the material. |
Functions is the math that does the correcting of structures against their materials.
Consider the following structure:
This type of locking is quite popular and is often used in corrugated designs. There are different views as to how the tongue height should be calculated:
Let's say Producer 1 thinks that the tongue height should be 1.5*material thickness; Producer 2 sees it as 2*material thickness.
To easily customize the entire library, (1) we have created the function THDC(d), which (2) is used in all resizable designs that have this type of locking.
The picture below shows how changing the expression of the function in the parameter template is reflected in the resizable design in which the function is used:
Another reason for using functions is to store complex expressions in a way that prevents the need of typing them each time you need them in parameter expressions.
You can successfully customize an entire library by simply modifying the functions in the parameter template applied to the structures in the library. Once a function is modified, the structures start behaving differently. Here's an example that changes the corrections controlling a structures sizes as a result of a new value of the material thickness.
The material thickness (d) affects the internal and external size of corrugated board structures. The functions PCI90(d) and PCO90(d) control the corrections that need to be applied to the structure to ensure that concrete values for the length, width, and height. By default, they are set to be half the material thickness, but if you need to apply a different rule, you do this by modifying their expressions.
You create and modify functions the Functions tab of the Edit Parameter Templates dialog box.
top of pageWhen we are creating a new resizable design, we can save time by appending parameters from the parameter template that comes with the material we are using. For example, every resizable design we create from scratch has the parameters L, W, H — for length, width and height, respectively. To save time, in the parameter template you can create these and other parameters in advance, and then use a single command to append them to the new drawing. In the following picture, four parameters are added to the parameter template.
To load these parameters, in the tabular area, in the Parameters tab, right-click, and then click Append default parameter templates.
The default parameters appear in the tabular area.
PROJECT-SPECIFIC PARAMETERS HAVE PRECEDENCE OVER DEFAULT ONES: Template parameters are not loaded automatically when you start a new project. If, after starting a project, you create your own parameters and then realize that you need the default ones, you may simply append them using the above procedure. In this case, if EngView detects identical parameters, it will append only the ones that have been missing. For example, if, after starting a project, you create a parameter H (for height), set an expression for it, and then append the default parameters for the current template, the parameter H set in the template will not be added; EngView will use the one you have created.
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