Data Types\Time

Time Interval 
This node calculates the time difference between
"Start", and "End" times. It stores the result in
an integer "Interval" out put. 
Update Time Variable
This node can be used to store time variables. 
Example
The example below demonstrates the use of both time nodes above. In it the value of "inisial_time" variable is updated upon Scene Start. Then when "Box" geometry is clicked the value of "current_time" variable is updated. Then the "Time Interval" node is executed, where "result" variable is calculated as difference between both times. 
In the experience the "result" variable is connected to
a Variable writer to display its value.