Use an Activation Condition node (
) to specify the conditions to dynamically enable or disable a user input, material property, feature input, material list, menu, menu item, or toggle item. The condition can depend on user inputs in the parent feature or property, or any other user input in a property within the physics interface. Conditions can either be true if the other user input has a specified value or if it is active. Right-click any feature node to add this subnode. Also right-click the
Activation Condition node to add an
Additional Requirement subnode. The
Settings window has the following section:
The activation condition can depend on user inputs in the parent feature, parent property, or some property. If the user input is under a feature or property, which can contain other user inputs, you can directly refer to any of those user inputs by choosing By reference in the
Specify user input list. From the
From list, choose
User input from this property, which you specify in the
Property field. You then choose the user input from the
User input list, and finally add or enter the values that activates the user input in the
Activating values list. This list differs depending on the type of user input you refer to. If you instead choose
Entity selection from the
From list, add or enter the values that activates the user input in the
Activating values list.
The other option in the Specify user input list is
By name, which means that you enter the name in the
User input field. The name is entered in the
Input name field of the user input you want to refer to. For the
By name option, the
From list only contains
User input from this property. You must also enter the type of the property that contains the user input in the
Property field. For Boolean user inputs, the values
Selected and
Not selected you enter as
0 and
1. You then choose the user input from the
User input list, and add or enter the values that activates the user input in the
Activating values list. Select the
Condition is not fulfilled for undefined references checkbox if an undefined reference should be treated as if the condition were not fulfilled.
The last option in the Specify user input list is
In expression. This is a general tool that can evaluate an expression of relations and Boolean operators that you specify in the
Condition field. It also supports some special functions and names, see the section about
Usage Condition for more details.
For all options in the Specify user input list, select the
Invert condition on input values checkbox to invert the entire condition. The
Require input is active checkbox is selected by default. It is only applicable when specifying a user input to check by reference or by name, not for expressions. When selected, the activation condition is only true if the checked user input is also active as decided by its activation conditions. For expressions, you can achieve the equivalent logic using the
isActive operator.
Nodes that define GUI elements can be hidden when disabled by an Activation Condition. For some nodes, hiding can be achieved by selecting an option on the node itself. For example, for a
User Input, the
Hide user input in GUI when inactive option can be selected to hide the element when disabled. For others, the GUI element can be hidden, when disabled, if placed in a
User Input Group with the
GUI option set to
Group members placed in a stack. For more information, see
Designing the GUI Layout.