Dear experts,
As per manual source rotation can be done using /gps/pos/rot1 and /gps/pos/rot2 command in macros . But what these two vectors represents as there is very less explanation in the manual[Geant4 General Particle Source — Book For Application Developers 11.0 documentation].
For example if I have to rotate a planer source +20 degree in z axis with respect to geometry axis. How to calculate these vectors.

Hi @rbyadav , /gps/pos/rot1 defines the first vector R1 (new x’ axis), [default (1,0,0)]. /gps/pos/rot2 defines the second vector R2(new y’ axis) in the xy plane, [default (0,1,0)].

Dear repan,
If I am correct then it means that R1 is new rotation x’ axis that makes (cos1, cos2,cos3) angles with original x,y,z axis of geometry and similar to R2??