Split-Based BVH Trees for Reduced Ray-Tracing Overlap
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Solution Overview
Problem
Conventional ray tracing techniques suffer from performance degradation due to overlapping bounding boxes in bounding volume hierarchies (BVH), particularly at higher levels of the hierarchy tree, leading to inefficient ray tracing operations.
Innovation Solution
Generate splitting planes during the construction of the BVH tree to prevent overlapping geometry at upper levels by classifying portions of geometry on opposing sides of the splitting planes, using methods such as random or median splitting, without relying on Morton codes or Surface Area Heuristics (SAHs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional BVH construction methods are used, then the ray tracing algorithm is simpler to implement, but overlapping bounding boxes occur at upper levels of the hierarchy tree causing performance degradation
Solution Approach 1:
The patent applies segmentation by dividing the geometry into multiple levels of hierarchy using splitting planes. Each level segments the space further, creating a multi-level bounding volume hierarchy that prevents overlapping at upper levels while maintaining organizational simplicity.
Solution Approach 2:
The patent introduces an additional dimensional aspect by using splitting planes that create hierarchical levels. This transforms the traditional single-level or simple hierarchical BVH into a multi-level structure where each level operates in an extended spatial dimension, preventing overlaps without complex algorithms.
2Productivity
If splitting planes are generated during BVH construction to prevent overlapping geometry, then redundant testing is reduced and efficiency improves, but the BVH construction process becomes more complex
Solution Approach 1:
The patent applies preliminary action by generating splitting planes and classifying geometry portions during the BVH construction phase itself, before ray tracing operations begin. This preliminary classification prevents overlapping geometry at upper levels, eliminating the need for redundant testing during actual ray tracing execution.
3Reliability
If geometry is classified on opposing sides of splitting planes, then overlapping bounding boxes are minimized, but the classification process requires additional computational resources
Solution Approach 1:
The patent applies self-service by having the geometry portions automatically classified during the BVH construction process itself. The splitting plane methodology inherently organizes geometry into opposing sides without requiring separate, resource-intensive classification operations later, as the classification is integrated into the tree construction.
Data Source
AI summary
Devices and methods are provided for generating an accelerated data structure for ray tracing which include generating a first splitting plane at a first location of a space comprising objects represented by geometry, constructing a first level of an accelerated data structure based on portions of the geometry, straddling the first splitting plane, which are classified as located on opposing sides of the first splitting plane, after constructing the first level of the accelerated data structure, generating a second splitting plane at a second location, different from the first location, of the space and constructing a second level of the accelerated data structure based on portions of the geometry, straddling the second splitting plane, which are classified as located on opposing sides of the second splitting plane.