Rendering transparent objects with caustics using real-time ray tracing. (May 2021)

• Record Type: Journal Article
• Authors: Wang, Xin; Zhang, Risong
• Is Part Of: Computers & graphics. Volume 96(2021)
• Page Start: 36
• Page End: 47
• Publication Date: 2021-05
• Subjects: Real-time ray tracing -- Transparency rendering -- Caustics; Computer graphics -- Periodicals; 006.6
• DOI: 10.1016/j.cag.2021.03.003
• Languages: English
• ISSNs: 0097-8493

Abstract

Highlights: Approximating the transparency phenomena using real-time ray tracing is a challenging problem. The rays classified by their behavior are easy to describe and simulate the light path. We proposed an improved method to render transparent objects by considering the volumetric absorption and rough transparency. We developed a method to approximates caustics by determining the point of incidence and tracing a light half path. Compared with the recent approaches, our model reaches higher visual quality. Graphical abstract: Abstract: After the release of the NVIDIA RTX platform, ray tracing methods are available in real-time rendering and improves the render quality. Therefore, realistic results can be produced in real time by combining ray tracing with rasterization techniques. However, rendering transparent objects with roughness and caustics in real time is still a challenge. We focus on these points and propose a model to render transparent objects based on real-time ray tracing. The model consists of two parts: Iterative Ray Tracing Transparency (IRTT) and Light Half Path Caustics (LHPC). IRTT approximates accurate reflections and refractions by tracing rays, computes volumetric absorption using the length that a ray propagates inside a transparent object, and simulates the rough transparency by bending the normal vector. Meanwhile, LHPC approximates caustics with a method named Local Light Tracing (LLT), where the main task is finding the point of incidence by tracing rays in the direction of the light source. After, a denoiser assisted by a distribution method is applied to suppress the noise. In the experiments, we design a combined pipeline and compare it with our model in terms of performance and render quality. In addition, our results are also compared with rasterization techniques. The experimental results reveal that our model improves the quality of the rendered image and offers a playable framerate.