Ray Tracing in Nvidia GPUs

Ray tracing method for metaverse implementation that reduces computational requirements by setting different paths of light based on distance between objects. The method involves generating a primary ray from the viewpoint, finding the first intersection point, checking the distance to other objects, and deriving the light path and sub-rays accordingly. This allows efficient ray tracing for complex scenes with dynamic objects by optimizing light propagation based on object proximity.

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Reducing the calculation amount for real-time ray tracing reflection rendering using a technique called adaptive subsampling. The method involves rendering a subset of pixels in the image at a lower resolution, then upscaling and combining the results. This selective low-res rendering reduces the overall calculation burden compared to ray tracing the entire image at full resolution. The key idea is to choose which pixels to render at low res based on a preset algorithm, like random selection or splitting into regions. This adaptive subsampling allows trading off accuracy for computational efficiency.

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A ray tracing based rendering method for computer graphics that improves rendering efficiency and quality. The method involves using ray tracing to generate rendering cache textures for each light source in a scene. These textures contain camera, geometry, material, and acceleration structure data. Denoising is applied to the textures. The textures are then merged and sampled to form the final rendered image. This allows reusing cached data for multiple light sources and accelerated ray tracing. The textures can be denoised separately for better quality.

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Real-time rendering of ambient light occlusion using ray tracing to improve the accuracy and efficiency of ambient lighting effects in real-time 3D rendering. The method involves ray tracing from each pixel to the scene geometry to find intersections, then sampling ambient light from spheres centered on those points to calculate occlusion. This provides realistic occlusion for moving objects and prevents issues like shadow artifacts.

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Method for accurately lighting virtual scenes in real-time rendering applications with complex, dynamic scenes. The method involves adaptive importance sampling of light sources in a scene using a cumulative distribution function (CDF). The CDF is generated based on importance estimates of lights in each voxel of the scene. This allows efficient sampling of lights for scene rendering by using the CDF to determine which lights are more important in a region. The CDF is updated as lights move or occlude to adapt to changing lighting conditions. Jittering voxel boundaries and light normal directions helps smooth out artifacts.

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Accelerating ray tracing and material shading on parallel processors like GPUs without adding transistors. The method involves compiling material graphs into optimized byte code instructions for execution on the parallel processing cores. The material graphs represent the surface properties and relationships of objects. The byte code is generated by parsing the graphs into expression trees and optimizing them. This allows efficient evaluation of the material graphs using the parallel processing cores without branching or sorting rays.

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Spectral rendering of images with volume media like mist, fog, dust, clouds, water, etc., that closely matches rendering in a multi-color scheme like RGB. The method involves identifying a light in a scene, determining an attenuation function characterizing interaction with the medium, fitting parameters based on minimizing color difference, and rendering using the attenuation function and fitted parameters. This allows realistic spectral rendering of lights transmitting through media that matches the appearance in a multi-color rendering.

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Render shadows in scenes with foliage like trees and bushes using a hybrid approach that improves performance and realism when ray-tracing shadows of alpha-tested geometry. The approach involves combining noisy visibility samples from raytraced opaque geometry with shadow maps that only contain alpha-tested geometry. This results in hybrid denoised shadows that show penumbras of high quality and hard ray-traced shadows at contact points with a low performance impact. The alpha-only shadow map only contains depth values from geometry that passes the alpha-test.

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Hybrid rendering technique that combines ray tracing and rasterization for realistic real-time 3D graphics. The method involves adaptive ray tracing scheduling to selectively use ray tracing for pixels with high potential for global illumination effects like reflections and refractions, while using rasterization for pixels with low potential. This allows focusing ray tracing resources on areas where it adds the most value. The adaptive scheduling is done before and after the ray tracing module.

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Optimizing motion vector estimation for translucent objects in images to improve rendering quality and reduce noise. The optimization involves accurately finding motion vectors for pixels in a current frame by searching for matching world positions in previous frames, even when objects are transparent. It uses numerical optimization techniques like Newton's method to minimize the angle between vectors instead of finding closest pixels. This improves performance over naive methods like random walks. The optimized motion vectors are then used for tasks like denoising and temporal anti-aliasing.

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Generating realistic water caustics in real-time gaming and animation applications that appear and move like actual physical caustics, while avoiding the need for expensive denoising procedures that can be computationally expensive or prohibitive for real-time use. The method involves using a low resolution caustics map with each point treated as a vector. These vectors are rendered as a mesh with connectors between adjacent points. When a hit point is detected, the position of the hit point replaces the original vertex position. This projected mesh provides sharp caustic patterns using fewer points compared to traditional denoising. The density of triangles is determined based on area to accurately represent brightness.

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Rendering signed distance functions (SDFs) in computer graphics more efficiently by improving techniques for tracing rays, computing surface normals, and finding ray intersections with SDF surfaces. The techniques involve: 1. Factorizing SDF coefficients into parameters to compute ray intersections with SDF surfaces using a cubic function. 2. Computing surface normals by interpolating neighboring voxel normals. 3. Finding ray intersections with SDF surfaces using turning points of the cubic function to determine shadowed regions. These techniques improve ray tracing and surface computation efficiency compared to duplicative calculations and separate ray tracing for shadows.

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Interleaving textures to improve ray tracing performance for scenes with incoherent light rays. Instead of separately allocating and accessing cache lines for each texture associated with an object intersected by a ray, the textures are combined into a single interleaved texture. This reduces the number of cache lines needed and less texture data is read compared to separately accessing each texture. The interleaved texture contains blocks from multiple textures alternating in order. It can be accessed using multiple texture headers with stride distances between blocks from the same texture. This allows fetching from the interleaved texture instead of separate textures for rays with incoherent intersections.

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Hardware acceleration of ray tracing for realistic graphics rendering that provides selective execution of programmable ray operations. The technique allows efficient and flexible ray intersection tests by enabling custom ray operations like selecting the level of detail (LOD) of an object. This improves ray tracing performance by allowing optimized ray operations for acceleration structures like BVHs that have mixed LOD models. It avoids the rigidity of requiring all nodes to support the same programmable ray operations. Instead, the ray operations can be applied selectively to nodes based on their data.

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Detecting penumbra regions for shadow denoising using wave intrinsic functions on parallel processors to avoid expensive post-processing for penumbra detection. The approach leverages threads of schedulable units (e.g., warps) used for visibility sampling during ray tracing to identify penumbra regions. Each thread computes a value indicating if its pixel region is in a penumbra using intrinsic functions. This avoids post-processing and allows selective denoising of penumbra regions vs fully lit/shaded regions. It also determines filter parameters based on sampling statistics to adapt denoising for regions.

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Hardware acceleration for real-time ray tracing to enable interactive ray tracing for applications like virtual reality and augmented reality. The acceleration is provided by a dedicated co-processor called a traversal coprocessor that sits in the graphics pipeline alongside the streaming processors. The coprocessor efficiently traverses an acceleration data structure like a bounding volume hierarchy to quickly determine ray intersections with scene objects. It handles tasks like ray-bounding volume intersection, ray-primitive intersection, and ray transforms. The coprocessor's dedicated hardware provides faster ray tracing compared to software ray tracing.

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Hardware-accelerated ray tracing that provides flexible and efficient ray intersection tests for real-time graphics. The technique allows combining ray operations like instance masking and geometric level of detail testing in parallel processing units. This improves ray tracing efficiency by enabling more complex ray tracing effects while simultaneously improving ray tracing efficiency. It allows dynamically choosing ray traversal based on multiple selection criteria per ray. The ray operations are configured to occur before and after node stack push/pop in the traversal coprocessor. This enables combining ray operations like instance masking and geometric level of detail testing in parallel processing units.

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Efficiently generating high quality images using techniques that allow efficient sampling of large emissive textures for lighting scenes. The method involves determining cumulative distribution functions for textures, constructing geometric representations from them, and tracing rays against the geometry to sample the textures efficiently. This hardware-accelerated sampling reduces noise compared to naive random sampling. The approach allows realistic lighting of scenes using large textures without incurring excessive computation cost.

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Rendering techniques for media like surfaces with microscopic irregularities and homogeneous slabs using position-free path integrals. It involves sampling directions of light passing through the medium, computing parameters for position distributions based on the directions, computing brightness at the exit direction using the distribution parameters, and rendering images based on the brightness. This approximates path integrals through the medium without the noise of Monte Carlo simulations.

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Techniques for sharing irradiance between ray interactions spatially and temporally to improve ray tracing performance for rendering virtual scenes. The method involves using irradiance caches to aggregate and interpolate irradiance samples instead of sampling from every location. Irradiance caches are associated with locations and updated by casting fewer rays based on ranking factors. Irradiance from other caches can be blended to compute irradiance at a location. This reduces the number of samples needed for lighting calculations compared to full ray tracing.

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