https://www.theverge.com/circuitbreaker/2018/8/20/17698314/nvidia-volta-gpu-ray-tracing-graphics

Ray tracing. It’s a term you’re going to hear a lot now that Nvidia has announced professional and consumer graphics cards that use this technique to produce some of the most life-like simulations possible in games and other animations. So, what is ray tracing exactly, and how does it differ from current graphics rendering techniques?

The oversimplified answer is that ray tracing models the behavior of light in real time as it intersects objects in a scene.