udf with moving heat source
 

I am modeling a laser beam scanning a surface in FLUENT and I am currently implementing the energy input from the laser in the form of a DEFINE_SOURCE udf. I would like to "translate" my laser across the substrate surface and watch the transient nature of the surrounding temperature profiles. In order to do so I need to somehow couple the solver "time" to the udf for each time step so I will know where to move the heat source depending on the new "time" value. I can not find how to get the time in the udf except for I see occasional use of RP_Get_Real function. Any help on this function or another way to read time in a udf would be appreciated.