how to define volme heat source in udf ?
 

hi,all my object is that a focused laser beam is radiated on a steel plate,a melting process is simulated. i want to define a volume source term using UDF,and know its position.if PROFILE MACRO or MOMENTUM SOURCE is used,"thead" argument is linked automatically by FLUENT,but what argument should be used when a Gaussian heat source(volume source) is used if its action position is known ?