Conditional Visibility

Apart from just showing or hiding certain objects you can also have their visibility status depend on a certain condition. For example, you would like an object to appear on screen if you check a checkbox positioned in the Graphics View or if a slider is changed to a certain value.

Conditionally Show or Hide Existing Objects

You can use the Check Box Tool in order to create a checkbox that controls the visibility of one or more existing objects on screen.

Alternatively, you could also create a Boolean variable (e.g. b = true) using the Input Bar and make it visible as a checkbox in the Graphics View by changing its visibility status (e.g. use Show / Hide Object Tool or the Context Menu). A checkbox therefore is a visible Boolean variable. In order to use this Boolean variable as a condition for the visibility of certain objects, you need to follow the steps described below.

Changing the Visibility of Newly Created Objects

In the Properties Dialog, you can enter a condition for the visibility of an object on tab Advanced.

You can select the logic operators (e.g. ≠, ≥, ˄, ‖) from list to the right of the input field in order to create your conditional statements.

If a is a slider, then the conditional statement a < 2 means that the corresponding object is only shown in the Graphics View if the slider value is less than 2.
If b is a Boolean variable, you can use b as a conditional statement. The corresponding object is shown whenever the value of b is true and is hidden when the value of b is false.
If g and h are two lines and you would like a text to be shown whenever these lines are parallel, then you could use g ‖ h as a conditional statement for the text.