Atmospheric environments don't exist in a vacuum! This session is a deep dive into the Volumetric Lighting technology developed by NVIDIA for Fallout 4. In it we review the physical principles behind how light is affected by the media it travels through, and go into the details of our approach. Finally we wrap up with a postmortem of its integration into Fallout 4, where we discuss overall performance and explore issues that developers might want to keep in mind when designing their own rendering pipelines.