17946509. EFFICIENCY OF RAY-BOX TESTS simplified abstract (NVIDIA Corporation)
Contents
- 1 EFFICIENCY OF RAY-BOX TESTS
EFFICIENCY OF RAY-BOX TESTS
Organization Name
Inventor(s)
Gregory Muthler of Chapel Hill NC (US)
John Burgess of Austin TX (US)
Eric Enderton of Berkeley CA (US)
Nikhil Dixit of Austin TX (US)
EFFICIENCY OF RAY-BOX TESTS - A simplified explanation of the abstract
This abstract first appeared for US patent application 17946509 titled 'EFFICIENCY OF RAY-BOX TESTS
Simplified Explanation
The efficiency of bounding volumes in a hardware-based ray tracer is improved by employing a sheared axis-aligned bounding box to approximate an oriented bounding box typically defined by rotations. The bounding volume hierarchy builder shears an axis-aligned box to tightly fit around its enclosed oriented geometry in top level or bottom level space, then computes the inverse shear transform. The bounds are stored as axis-aligned boxes in memory, now defined in the new sheared coordinate system, along with the derived parameters to transform a ray into the sheared coordinate system before testing intersection with the boxes. The ray-bounding volume intersection test is performed in the new sheared coordinate system. Additional efficiencies are gained by constraining the number of shear dimensions, constraining the shear transform coefficients to a quantized list, sharing a shear transform across a collection of bounds, performing a shear transform only for ray-bounds testing and not for ray-geometry intersection testing, and adding a specialized shear transform calculator/accelerator to the hardware.
- Sheared axis-aligned bounding box used to approximate oriented bounding box
- Bounding volume hierarchy builder shears axis-aligned box to fit tightly around enclosed oriented geometry
- Inverse shear transform computed for efficient ray-bounding volume intersection testing
- Additional efficiencies gained through various constraints and optimizations
Potential Applications
The technology can be applied in real-time rendering, virtual reality, augmented reality, gaming, and computer-aided design (CAD) software.
Problems Solved
1. Improved efficiency in bounding volume calculations in hardware-based ray tracing 2. Accurate approximation of oriented bounding boxes with sheared axis-aligned boxes
Benefits
1. Faster ray tracing performance 2. Reduced memory usage 3. Enhanced accuracy in bounding volume calculations
Potential Commercial Applications
Optimizing ray tracing performance in video games, architectural visualization software, and medical imaging applications.
Possible Prior Art
Prior art may include techniques for optimizing bounding volume calculations in ray tracing algorithms, such as using bounding volume hierarchies or spatial partitioning methods.
Unanswered Questions
How does the sheared axis-aligned bounding box approach compare to other methods in terms of performance and accuracy?
The article does not provide a direct comparison with other methods for bounding volume approximation in hardware-based ray tracing.
What are the potential limitations or drawbacks of using a sheared axis-aligned bounding box for approximating oriented bounding boxes?
The article does not address any potential limitations or drawbacks of the proposed approach.
Original Abstract Submitted
To improve the efficiency of bounding volumes in a hardware based ray tracer, we employ a sheared axis-aligned bounding box to approximate an oriented bounding box typically defined by rotations. To achieve this, the bounding volume hierarchy builder shears an axis-aligned box to fit tightly around its enclosed oriented geometry in top level or bottom level space, then computes the inverse shear transform. The bounds are still stored as axis-aligned boxes in memory, now defined in the new sheared coordinate system, along with the derived parameters to transform a ray into the sheared coordinate system before testing intersection with the boxes. The ray-bounding volume intersection test is performed as usual, just in the new sheared coordinate system. Additional efficiencies are gained by constraining the number of shear dimensions, constraining the shear transform coefficients to a quantized list, sharing a shear transform across a collection of bounds, performing a shear transform only for ray-bounds testing and not for ray-geometry intersection testing, and adding a specialized shear transform calculator/accelerator to the hardware.
