Ray-Object Intersection Testing Using Contained Bounding Regions
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Solution Overview
Problem
Existing ray tracing systems face inefficiencies in determining intersections with objects, particularly in parallel traversal algorithms, leading to unnecessary computational effort and power consumption due to the need to test nodes that are often occluded, and the complexity of traversing acceleration structures is exacerbated by the presence of complex or detailed surfaces.
Innovation Solution
A method for determining intersections by testing rays against bounding regions within an object partitioning hierarchy, allowing for early determination of intersections without the need to traverse to leaf nodes, using conservative hit tests based on bounding regions to reduce the number of intersection tests required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If parallel traversal algorithms are used to traverse acceleration structures, then processing speed is improved, but the number of unnecessary intersection tests on occluded nodes increases
Solution Approach 1:
The patent introduces a preliminary culling step that determines whether a node is occluded before performing expensive intersection tests. By evaluating bounding volume intersections first and culling occluded nodes early in the traversal process, the system avoids unnecessary processing of hidden surfaces, thereby reducing power consumption while maintaining parallel traversal speed advantages
2Measurement precision
If traditional ray tracing methods traverse to leaf nodes to determine intersections, then intersection accuracy is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent segments the intersection determination process into two distinct phases: a coarse phase using bounding volume hierarchy (BVH) for rapid occlusion culling, and a fine phase using contained region intersection tests for precise intersection determination. This segmentation allows the system to achieve accurate intersection results without traversing the entire acceleration structure to leaf nodes, thereby reducing computational complexity while maintaining precision
3Productivity
If conservative hit tests using bounding regions are used, then the number of intersection tests is reduced, but the precision of intersection detection may be compromised
Solution Approach 1:
The patent introduces contained regions as intermediary geometric primitives that bridge the gap between coarse bounding volumes and detailed object surfaces. These contained regions are positioned within objects and serve as intermediate test targets that provide more precise intersection detection than bounding volumes alone, while still being simpler than full surface intersection tests. This intermediary approach maintains high productivity while improving detection precision
Data Source
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AI summary
Object intersection testing in a ray tracing system. There is provided a method of determining, in a ray tracing system, whether a ray intersects an object of a scene, wherein the object is contained within a union of one or more bounding regions that are finite, wherein the one or more bounding regions form part of an object partitioning hierarchy. The method comprises determining that the ray intersects a region defined by the union of the one or more bounding regions, obtaining at least one contained region, wherein each at least one contained region is contained within, and smaller than, extents of a geometry defined by the object, determining that the ray intersects a contained region of the at least one contained region, and determining whether the ray intersects the object in dependence on at least determining that the ray intersects the contained region.