Improved ray tracing performance through tri-adaptive sampling

Tristan Craddick
Wed, 22 Apr 2026 17:42:42 PDT

Ray tracing is a technique capable of rendering high quality images by tracing rays from the camera position into the scene and examining the points they intersect with. With the advent of NVIDIA RTX hardware, improving renderer design through greater algorithmic efficiency will allow for even greater real-time rendering capabilities. Naive implementations are simple to implement and cheap enough to run well on modern systems, but often have issues with aliased edges due to lower quantities of rays for scene sampling. Techniques such as super-sampling are capable of reducing or entirely eliminating aliasing, but carry a high performance cost due to additional ray requirements. Under-sampling is a technique that allows a single ray to determine the color of multiple pixels, allowing for high performance in regions of little variation. The combination of these techniques is collectively referred to as Adaptive Sampling. Our implementation of this algorithm operates by rendering the scene at a low resolution and then sampling the resulting image to determine if rays are necessary at higher resolutions. In this project, we implement a form of this multiple-resolution approach based upon a triangular grid overlaying the pixel grid. Results on RTX cards indicate a performance increase of 29-40% over the naive renderer, and a 1-4% increase over the traditional adaptive sampling algorithm, all while achieving little degradation in quality compared to the ground truth image.