atomicAdd(&out5[0], 1) does not work in the RT_Program closest_hit_radiance1 in . However, it works and gives result in pinhole_camera or closest_hit_object RT_Program functions.Is a there a missing point i did not understand? How can i run atomicAdd inside closest hit function?

“Does not work” is an insufficient problem description on any developer forum.

There is no out5 buffer or closest_hit_object program in any OptiX example code.
Maybe start explaining what code changes you did exactly and what the problem is you’re experiencing.

Please always include the following system information when reporting OptiX issues to reduce turnaround times:
OS version, installed GPU(s), display driver version, OptiX versions (major.minor.micro), CUDA toolkit version used to compile the PTX code.