Not from a GDC presentation, but perhaps a useful reference none the less, the complete version of Ray Tracing Gems is available free for download --
https://link.springer.com/book/10.1007/978-1-4842-4427-2
GPU-Based Procedural Placement in Horizon Zero Dawn
https://www.guerrilla-games.com/read/gpu-based-procedural-placement-in-horizon-zero-dawn