Hierarchical Ray Tracing Structures for Low-Bandwidth Traversal

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Solution Overview

Problem

Existing ray tracing systems face challenges in reducing data transfer and computational latency while maintaining real-time rendering performance, particularly in mobile devices, due to large acceleration structure data and memory bandwidth limitations.

Innovation Solution

Implementing a hierarchical acceleration structure with implicitly represented nodes, where data defining the region is inferred from descendant nodes, reducing the amount of data stored and transferred, and dynamically adjusting the traversal based on system conditions to optimize memory usage and throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If acceleration structure data is stored explicitly for all nodes, then intersection testing accuracy is maintained, but data transfer and memory bandwidth requirements increase

Engineering Contradiction:
Improveintersection testing accuracyVSAvoiddata transfer volume
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the necessary data for intersection testing by omitting redundant node information. Instead of storing complete acceleration structure data for all nodes, the system extracts and stores only descendant node data that is actually needed for ray intersection tests, reducing memory bandwidth requirements while maintaining testing accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a simplified copy of the acceleration structure data suitable for mobile devices. Rather than transferring the complete high-fidelity acceleration structure, the system creates a reduced copy containing only essential intersection testing data, enabling accurate rendering with limited memory bandwidth.

Inventive Principle:
Principle #26Copying

2Manufacturing precision

If complete acceleration structure data is transferred to memory, then rendering quality is maintained, but power consumption and data transfer time increase

Engineering Contradiction:
Improverendering qualityVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The system extracts only the essential acceleration structure data needed for maintaining rendering quality on mobile devices. By removing redundant node information and transferring only necessary descendant data, the patent reduces power consumption associated with memory operations while preserving visual fidelity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Quantity of substance

If hierarchical acceleration structure with implicit nodes is used, then data storage is reduced, but computational complexity for inferring node data increases

Engineering Contradiction:
Improvedata storage volumeVSAvoidcomputational complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent implements self-service by enabling the system to automatically infer missing acceleration structure node data from available descendant node information during runtime. This eliminates the need to store redundant data while the computation is performed on-demand using simple geometric calculations based on descendant node bounds.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3929879B1Hierarchical acceleration structures for use in ray tracing systems
Publication Date: 2026.03.25 IMAGINATION TECH LTD
  • EP3929879B1 patent drawingFigure 1
  • EP3929879B1 patent drawingFigure 2a~2b
  • EP3929879B1 patent drawingFigure 3

AI summary

Ray tracing systems and computer-implemented methods are described for generating a hierarchical acceleration structure to be used for intersection testing in a ray tracing system. Nodes of the hierarchical acceleration structure are determined, wherein each of the nodes represents a region in a scene, and wherein the nodes are linked to form the hierarchical acceleration structure. Data is stored representing the hierarchical acceleration structure. The stored data comprises data defining the regions represented by a plurality of the nodes of the hierarchical acceleration structure. At least one node of the hierarchical acceleration structure is an implicitly represented node, wherein data defining a region represented by an implicitly represented node is not explicitly included as part of said stored data but can be inferred from said stored data. Also described are ray tracing systems and computer-implemented methods for performing intersection testing in the ray tracing system in which, based on conditions in the ray tracing system, a determination is made as to whether testing of one or more rays for intersection with a region represented by a particular node of a sub-tree is to be skipped. The one or more rays are tested for intersection in accordance with said determination.