Ray Tracing Intersection Tests Using Contained Bounding Regions
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Solution Overview
Problem
Existing ray tracing systems face inefficiencies in intersection testing due to the need to traverse hierarchical acceleration structures to determine intersections, particularly in parallel traversal algorithms, leading to excessive computational effort and power consumption.
Innovation Solution
A method for conservatively determining intersection with objects by testing against bounding regions within the acceleration structure, allowing intersection existence to be determined without traversing to leaf nodes, thereby reducing 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 increases leading to excessive computational effort
Solution Approach 1:
The patent applies partial action by implementing early exit conditions in parallel traversal algorithms. When a ray intersects an object, the algorithm terminates further traversal for that ray immediately, performing only the necessary intersection tests rather than exhaustively testing all nodes. This reduces computational effort while maintaining parallel processing speed advantages.
Solution Approach 2:
The patent segments the traversal process by dividing rays into groups that can be processed in parallel while implementing independent early exit logic for each ray. This allows the system to benefit from parallel processing without the excessive computational overhead of testing all nodes for every ray, as each ray's traversal is independently optimized to stop when its intersection is found.
2Productivity
If hierarchical acceleration structures with multiple levels are used, then the number of intersection tests is reduced, but traversal complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-computing and storing traversal hints and early exit conditions in the acceleration structure during the build phase. This allows the traversal algorithm to make informed decisions about when to stop traversing without complex runtime calculations, reducing both the number of intersection tests and the complexity of the traversal logic.
Solution Approach 2:
The patent introduces intermediary data structures and traversal hints that mediate between the hierarchical acceleration structure and the ray traversal algorithm. These intermediaries encode traversal information in advance, allowing the algorithm to navigate the hierarchy efficiently without complex runtime decision-making, thus reducing both intersection tests and traversal complexity.
3Measurement precision
If leaf node traversal is required to determine intersection, then accuracy is improved, but computational effort increases significantly
Solution Approach 1:
The patent applies partial action by implementing early exit conditions that allow the algorithm to determine intersections without always traversing to leaf nodes. When an intersection is detected at an intermediate node, the algorithm terminates further traversal for that ray, performing only the necessary tests to achieve accurate intersection determination while significantly reducing computational effort and power consumption.
Data Source
AI summary
Object intersection testing in a ray tracing system determines whether a ray intersects an object of a scene, wherein the object is contained within a bounding region that is finite and forms part of an object partitioning hierarchy. Upon determining that the ray intersects the bounding region, at least one contained region is obtained, wherein the contained region is contained within, and smaller than, extents of a geometry defined by the object. Upon determining that the ray intersects a contained region of the at least one contained region, it is determined whether the ray intersects the object in dependence on at least determining that the ray intersects the contained region.