Hybrid Rasterization Ray Tracing Soft Shadow Rendering
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Solution Overview
Problem
Current 3-D rendering technologies face challenges in accurately modeling occlusion from area lights, particularly in achieving soft shadow effects, as they often require high computational resources and are not optimized for real-time rendering, with traditional ray tracing being inefficient for maintaining frame rates and rasterization-based systems struggling to faithfully represent light behavior.
Innovation Solution
A hybridized rendering approach that uses rasterization to identify visible surfaces and then employs ray tracing for occlusion sampling, with a sampling strategy defined in screen space, where a pattern of ray directions is tiled across the frame, allowing for predictable ray tracing and blending of results to achieve accurate soft shadow representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ray tracing is used for high quality rendering, then rendering quality is improved, but frame rate deteriorates
Solution Approach 1:
The patent segments the rendering process into two distinct passes: a rasterization pass that identifies visible surfaces at each pixel, and a ray tracing pass that samples occlusion only for those visible surfaces. This segmentation allows the system to leverage the speed of rasterization for visibility determination while using ray tracing only where necessary for accurate shadow rendering, thus maintaining quality without sacrificing frame rate
Solution Approach 2:
The patent applies partial ray tracing by performing ray tracing operations only for pixels that contain visible surfaces, rather than for all pixels in the frame. The ray tracing is used partially to determine occlusion for soft shadow effects, combining this partial application with rasterization results to achieve high quality rendering at real-time frame rates
2Productivity
If rasterization-based rendering is used for real-time performance, then frame rate is improved, but rendering quality deteriorates
Solution Approach 1:
The patent merges rasterization and ray tracing techniques into a hybridized rendering pipeline. The rasterization pass provides efficient visible surface identification, while the ray tracing pass adds accurate occlusion sampling for soft shadow effects. By combining these two techniques, the system achieves both real-time frame rates and high rendering quality that faithfully represents light behavior
Solution Approach 2:
The patent applies ray tracing partially within the rasterization pipeline, using it only for occlusion sampling of area lights to generate soft shadows. This partial application of ray tracing enhances rendering quality for specific lighting effects while maintaining the overall efficiency of rasterization for real-time performance
3Measurement precision
If ray tracing is used for occlusion sampling, then rendering quality is improved, but computational resources increase
Solution Approach 1:
The patent segments the frame into pixels with visible surfaces and pixels without, using rasterization to identify only the relevant pixels. Ray tracing for occlusion sampling is then applied only to this segmented subset of pixels, significantly reducing the total number of ray tracing operations required while maintaining accurate occlusion representation for area lights
Solution Approach 2:
The patent applies ray tracing partially by using it only for occlusion sampling of area lights rather than for all lighting calculations. This partial application reduces computational resource consumption compared to full ray tracing, while still achieving accurate soft shadow effects where they are most needed
Data Source
AI summary
Systems can identify visible surfaces for pixels in an image (portion) to be rendered. A sampling pattern of ray directions is applied to the pixels, so that the sampling pattern of ray directions repeats, and with respect to any pixel, the same ray direction can be found in the same relative position, with respect to that pixel, as for other pixels. Rays are emitted from visible surfaces in the respective ray direction supplied from the sampling pattern. Ray intersections can cause shaders to execute and contribute results to a sample buffer. With respect to shading of a given pixel, ray results from a selected subset of the pixels are used; the subset is selected by identifying a set of pixels, collectively from which rays were traced for the ray directions in the pattern, and requiring that surfaces from which rays were traced for those pixels satisfy a similarity criteria.