Bounding Interval Hierarchy for Dynamic Ray Tracing

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Solution Overview

Problem

Current ray tracing techniques face limitations in processing dynamic scenes, with high memory requirements and slow setup times for acceleration data structures, leading to inefficiencies in rendering fully animated scenes and motion blur in motion pictures.

Innovation Solution

A hierarchical ray tracing acceleration data structure is constructed using a bounding interval hierarchy, where objects are partitioned into left and right sets based on axis-aligned bounding boxes and parallel planes, allowing for efficient construction and traversal, and memory is managed to ensure linear growth with the number of objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional 3D-tree acceleration structures are used for ray tracing, then rendering capability is provided, but setup time increases significantly and memory requirements grow quadratically with the number of objects

Engineering Contradiction:
Improverendering capabilityVSAvoidsetup time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent segments the scene into multiple bounding volumes organized in a hierarchical structure. Each bounding volume contains a subset of objects, allowing the system to process only relevant portions of the scene during ray tracing. This segmentation enables efficient setup time by pre-organizing objects in a way that reduces the computational burden during actual rendering operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary organization of objects into bounding volumes and hierarchical structures before actual ray tracing begins. This pre-processing step creates acceleration data structures that can be quickly traversed during rendering, significantly reducing the setup time required for each rendering operation while maintaining the ability to handle large numbers of objects efficiently.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If traditional 3D-tree acceleration structures are used for ray tracing, then rendering capability is provided, but memory footprint increases quadratically with the number of objects

Engineering Contradiction:
Improverendering capabilityVSAvoidmemory footprint
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent divides the scene into hierarchical bounding volumes where each level contains only the objects relevant to that spatial region. This segmentation allows the system to store and process only the necessary object information at each hierarchy level, preventing quadratic memory growth. The bounding volume hierarchy ensures that memory requirements scale linearly with the number of objects rather than quadratically.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent pre-organizes objects into bounding volumes and hierarchical structures before rendering begins. This preliminary organization creates compact data structures that efficiently represent the scene geometry, reducing the total memory footprint. By establishing this hierarchical organization in advance, the system avoids the need to store redundant information during actual rendering operations.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If bounding volume hierarchies are used to improve performance, then system performance increases, but the architecture breaks down when too many incoherent secondary rays are traced

Engineering Contradiction:
Improvesystem performanceVSAvoidperformance stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a dynamic ray tracing approach that adapts to different rendering scenarios. The bounding volume hierarchy is traversed flexibly, allowing the system to handle both coherent and incoherent secondary rays effectively. The hierarchical structure enables dynamic adjustment of the tracing path based on the specific rendering requirements, maintaining performance stability even when dealing with complex light paths and multiple ray types.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2008249B1Instant ray tracing
Publication Date: 2013.07.17 NVIDIA CORP
  • EP2008249B1 patent drawingFigure 1
  • EP2008249B1 patent drawingFigure 2A
  • EP2008249B1 patent drawingFigure 2B

AI summary

Methods, systems, devices and computer program products operable in a computer graphics system include constructing a hierarchical ray tracing acceleration data structure comprising a tree structure, the nodes of which are generated utilizing a bounding interval hierarchy based on defining an axis-aligned scene bounding box and two parallel planes to partition a set of objects in a scene into left objects and right objects, and matching split planes to object bounding boxes. The two planes are perpendicular to a selected one of x, y, or z-axes. Given a splitting plane, each object in an image is classified either left or tight based on a left/right selection criterion, and two splitting plane values of the child nodes are determined by the maximum and minimum coordinate of the left and right objects, respectively.