Open Physics Topical Spotlights

Digital Rendering, Image Rasterization, and Ray Tracing Heuristics

On October 4, 2019, Patryk Walewski, Tomasz Gałaj, and Dominik Szajerman have published an article entitled “Heuristic based real-time hybrid rendering with the use of rasterization and ray tracing method” in Open Physics.

A Blog Post by Pablo Markin.

In their paper, Patryk Walewski, Tomasz Gałaj, and Dominik Szajerman present “a hybrid approach for real-time rendering using both rasterization and ray tracing using heuristic” (527) that are commonly deployed for achieving photorealistic visual effects in interactive digital environments, such as games, in real-time. As these authors explicate, “[t]he first rendering method that was widely used in generating images in real-time was rendering using rasterization […] not only in computer graphics, but also in scientific or database field […][, while] more photorealistic results in rendering images […] [could be attained via] ray tracing” (527). This article, thus, discusses “[t]he initial work introducing full recursive ray tracing idea […] proposed […] by Turner Whitted […]. In this algorithm, primary rays were responsible for geometry detection and base surface color calculations, where the secondary rays were responsible for additional effects – reflections, refractions and shadows” (528).

As these researchers indicate, “[r]ecently, two promising APIs [(application programming interfaces)] were […] released that provide support for implementing GPU [(graphics processing unit)-based] ray tracing algorithms. Those are DirectX Ray Tracing API (DXR) and NVIDIA RTX API [, which is a graphics rendering development platform]” (530). This article, consequently, describes a rendering solution that “allows rendering scenes using hybrid rendering [algorithms], in which four stages can be distinguished” (530), which comprise a rasterization stage, a heuristic stage, a ray tracing stage and a blending stage. To examine the correctness this solution, Walewski, Gałaj, and Szajerman “have performed two sets of tests each performed in four different scenes” (529).

The results of these tests have indicated that the “presented solution is capable of making ray tracing a method that may be used in real-time interactive applications, especially with the use of high-end graphic cards […] [with greater] computing power” (541). As this article suggests, the use of contemporary high-performing GPUs makes it possible “to perform ray tracing along with rasterization stage and maintain the real-time characteristic of [its] application[s]” (541-542).

By Pablo Markin

Featured Image Credits: Photoshop Fixes: Challenge 50, March 26, 2010 | © Courtesy of Matt Lindley/Flickr.

Cite this article as: Pablo Markin, "Digital Rendering, Image Rasterization, and Ray Tracing Heuristics," in Discussions Générales Open, 23/11/2019,


Walewski, Patryk, Tomasz Gałaj, and Dominik Szajerman. “Heuristic based real-time hybrid rendering with the use of rasterization and ray tracing method.” Open Physics 17.1 (2019): 527-544.

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