Real-time Ray Tracing Research Articles

ПРОЕКТИРОВАНИЕ И ДИЗАЙН ИЗДЕЛИЯ В CAD/CAM/CAE СИСТЕМЕ NX ПОД УПРАВЛЕНИЕМ PLM СИСТЕМЫ TEAMCENTER

The article discusses a system widely implemented in the designing of equipment for the NX construction industry. Along with this system, a modern automation tool was used. The most common and most used products are Siemens products: PLM-system "Teamcenter". The functionality of this configuration is huge, it includes such applications a "Manager of Structure", "Classifier", "Advanced Studio", "Ray Tracing Studio", etc. For example, it is possible to create a single product structure with various configurations, machine components and assemblies, using the "Structure Manager". This structure allows to simplify the introduction of changes and the development of a digital electronic model. For the final visualization and rendering, the NX system provides a certain set of tools, which includes "Extended Studio" and "Ray Tracing Studio". "Advanced Studio" is an application allowing to get high-quality image, including the effects of materials, textures, lighting, shadows and reflections for the product in the CAD/CAM/CAE NX system. "Ray Tracing Studio" allows to get the rendering of the future product. In the Ray Tracing Studio editor, it is possible to configure such parameters as dynamic tracing setting, real-time ray tracing setting, display static high-quality tracing setting, and general display settings. Creation of a product in this system can be considered by the example of a digital electronic model of a roller support.

Spatiotemporal reservoir resampling for real-time ray tracing with dynamic direct lighting

Efficiently rendering direct lighting from millions of dynamic light sources using Monte Carlo integration remains a challenging problem, even for off-line rendering systems. We introduce a new algorithm---ReSTIR---that renders such lighting interactively, at high quality, and without needing to maintain complex data structures. We repeatedly resample a set of candidate light samples and apply further spatial and temporal resampling to leverage information from relevant nearby samples. We derive an unbiased Monte Carlo estimator for this approach, and show that it achieves equal-error 6×-60× faster than state-of-the-art methods. A biased estimator reduces noise further and is 35×-65× faster, at the cost of some energy loss. We implemented our approach on the GPU, rendering complex scenes containing up to 3.4 million dynamic, emissive triangles in under 50 ms per frame while tracing at most 8 rays per pixel.

Implementation of Autoencoder based Neural Network for Realtime Ray Tracing

Implementation of Autoencoder based Neural Network for Realtime Ray Tracing

Ray Tracing Dynamic Scenes Using Multiple Kd-trees

With faster hardware and algorithmic improvements, real-time ray tracing is finally within reach. A variety of different data structures have been developed for ray tracing over the past decades. These spatial data structures crucial for fast ray tracing must be rebuilt or updated as the scene changes, and this can become a bottle-neck for the speed of ray tracing. In this paper, a novel algorithm is proposed to improve the rendering speed for static and moving objects by build kd-trees respectively, i.e., we construct multiple kd-trees. This building method allows for ray tracing animations without rebuilding the spatial index structures for the whole scene, just for dynamic objects. We implement the proposed algorithm for ray tracing dynamic scene on CPU+GPU platform, resulting in frame rates of 3~5 fps for 1024*1024 images, which improves rendering speed of dynamic scenes significantly.

PLOCTree

In the near future, GPUs are expected to have hardware support for real-time ray tracing in order to, e.g., help render complex lighting effects in video games and enable photorealistic augmented reality. One challenge in real-time ray tracing is dynamic scene support, that is, rebuilding or updating the spatial data structures used to accelerate rendering whenever the scene geometry changes. This paper proposes PLOCTree, an accelerator for tree construction based on the Parallel Locally-Ordered Clustering (PLOC) algorithm. Tree construction is highly memory-intensive, thus for the hardware implementation, the algorithm is rewritten into a bandwidth-economical form which converts most of the external memory traffic of the original software-based GPU implementation into streaming on-chip data traffic. As a result, the proposed unit is 3.9 times faster and uses 7.7 times less memory bandwidth than the GPU implementation. Compared to state-of-the-art hardware builders, PLOCTree gives a superior performance-quality tradeoff: it is nearly as fast as a state-of-the-art low-quality linear builder, while producing trees of similar Surface Area Heuristic (SAH) cost as a comparatively expensive binned SAH sweep builder.

MergeTree

Ray tracing is a computationally intensive rendering technique traditionally used in offline high-quality rendering. Powerful hardware accelerators have been recently developed that put real-time ray tracing even in the reach of mobile devices. However, rendering animated scenes remains difficult, as updating the acceleration trees for each frame is a memory-intensive process. This article proposes MergeTree, the first hardware architecture for Hierarchical Linear Bounding Volume Hierarchy (HLBVH) construction, designed to minimize memory traffic. For evaluation, the hardware constructor is synthesized on a 28nm process technology. Compared to a state-of-the-art binned surface area heuristic sweep (SAH) builder, the present work speeds up construction by a factor of 5, reduces build energy by a factor of 3.2, and memory traffic by a factor of 3. A software HLBVH builder on a graphics processing unit (GPU) requires 3.3 times more memory traffic. To take tree quality into account, a rendering accelerator is modeled alongside the builder. Given the use of a toplevel build to improve tree quality, the proposed builder reduces system energy per frame by an average 41% with primary rays and 13% with diffuse rays. In large ( > 500K triangles) scenes, the difference is more pronounced, 62% and 35%, respectively.

Foveated Real-Time Ray Tracing for Head-Mounted Displays

Head-mounted displays with dense pixel arrays used for virtual reality applications require high frame rates and low latency rendering. This forms a challenging use case for any rendering approach....

Ray tracing propagation modeling for future small-cell and indoor applications: A review of current techniques

Applied for the first time to mobile radio propagation modeling at the beginning of the nineties, ray tracing is now living a second youth. It is probably the best model to assist in the design and planning of future short-range, millimeter-wave wireless systems, where the more limited propagation environment with respect to UHF frequencies allows to overcome traditional high-CPU time limitations while the higher operating frequency makes ray-optics approximations less drastic and allows to achieve an unprecedented level of accuracy. An overview of ray tracing propagation modeling is given in this paper, with a special attention to future prospects and applications. In particular, frontiers of ray-based propagation modeling such as extension to diffuse scattering, multidimensional channel characterization, multiple-input multiple-output (MIMO) capacity assessments, and future applications such as real-time ray tracing are addressed in the paper with reference to the work recently carried out at the University of Bologna.

Ray tracing-based interactive diffuse indirect illumination

Despite great efforts in recent years to accelerate global illumination computation, the real-time ray tracing of fully dynamic scenes to support photorealistic indirect illumination effects has ye...

Real-time Ray-tracing Chip Architecture

In this paper, we describe the world’s first real-time ray-tracing chip architecture. Raytracing technology generates high-quality 3D graphics images better than current rasterization technology by providing four essential light effects: shadow, reflection, refraction and transmission. The real-time ray-tracing chip named RayChip includes a real-time ray-tracing graphics processing unit and an accelerating tree-building unit. An ARM Ltd. central processing unit (CPU) and other peripherals are also included to support all processes of 3D graphics applications. Using the accelerating tree-building unit named RayTree to minimize the CPU load, the chip uses a low-end CPU and decreases both silicon area and power consumption. The evaluation results with RayChip show appropriate performance to support real-time ray tracing in high-definition (HD) resolution, while the rendered images are scaled to full HD resolution. The chip also integrates the Linux operating system and the familiar OpenGL for Embedded Systems application programming interface for easy application development.

Real-time multiply recursive reflections and refractions using hybrid rendering

We present a new method for real-time rendering of multiple recursions of reflections and refractions. The method uses the strengths of real-time ray tracing for objects close to the camera, by sto...

FPGA Hardware Acceleration for Visualization with Use of the Ray Tracing Algorithm

This paper deals with the issue of hardware acceleration of photorealistic visualization with use of ray tracing technique in real time. First part of the article briefly introduces ray tracing and presents existing hardware architectures that are accelerating computations with aim to bring real time ray tracing; second part of the article introduces the implementation of the designed solution that represents two modules implemented with use of the VHDL language and the FPGA technology. Modules are accelerating the part of ray tracing algorithm that according to the research requires the most system resources. This part consists of computation needed to find the ray-object intersection. The first module computes ray – sphere intersection, and the second computes ray – triangle intersection. Both modules are composed of number of components, which were optimized and parallel computing was applied in highest possible measure.

Improving Memory Space Efficiency of Kd-tree for Real-time Ray Tracing

Compared with its competitors such as the bounding volume hierarchy, a drawback of the kd-tree structure is that a large number of triangles are repeatedly duplicated during its construction, which often leads to inefficient, large and tall binary trees with high triangle redundancy. In this paper, we propose a space-efficient kd-tree representation where, unlike commonly used methods, an inner node is allowed to optionally store a reference to a triangle, so highly redundant triangles in a kd-tree can be culled from the leaf nodes and moved to the inner nodes. To avoid the construction of ineffective kd-trees entailing computational inefficiencies due to early, possibly unnecessary, ray-triangle intersection calculations that now have to be performed in the inner nodes during the kd-tree traversal, we present heuristic measures for determining when and how to choose triangles for inner nodes during kd-tree construction. Based on these metrics, we describe how the new form of kd-tree is constructed and stored compactly using a carefully designed data layout. Our experiments with several example scenes showed that our kd-tree representation technique significantly reduced the memory requirements for storing the kd-tree structure, while effectively suppressing the unavoidable frame-rate degradation observed during ray tracing.

Node pre-fetching architecture for real-time ray tracing

Node pre-fetching architecture for real-time ray tracing

Study on Scene Rendering Using Ray Tracing

The paper synoptically discusses the basic technological process of the ray tracing method, analyzes its parallel algorithms. Introduce the recent research focus of the field from study on real-time ray tracing and based ray tracing of graphics hardware. Point out the advantages and disadvantages of the ray tracing algorithms to solve scene rendering as well as future research priorities.

Visual realism enhances realistic response in an immersive virtual environment--part 2.

Does realistic lighting in an immersive VR application enhance presence--that is, the participants' feeling that they're actually in the scene and behaving accordingly? Part 1 of this study indicated that presence is more likely with real-time ray tracing than with ray casting. However, that research couldn't separate the effects of overall illumination quality from the dynamic effects of real-time shadows and reflections. In a new experiment, 20 people experienced a scene rendered with either global or local illumination. Both conditions included dynamically changing shadows and reflections. Illumination quality didn't affect presence, so the earlier result must have been caused by dynamic shadows and reflections. Nevertheless, global illumination did result in greater plausibility--that is, participants were more likely to respond as if the virtual events were real. These results indicate that global illumination does affect participant responses and is worth the effort.

The MHD Control System for the FTU Tokamak

In this paper the architecture of the MHD control system for the Frascati Tokamak Upgrade (FTU) is presented. This control is aimed to stabilize tearing modes (TM) in the plasma by EC heating and current drive. TMs are detected and spatially localized by correlating several ECE channels and Mirnov coil signals; two independent antennas are steered in order to track the TM instability. To guarantee short locking time a fast real-time plasma equilibrium code is used to locate the instability when there is no TM evidence and real-time ray tracing code is used to estimate the location where EC power is deposited. A set of hardware consisting of FPGA and DSP modules on PXI bus for executing the diagnosis and control algorithms is proposed. The overall system layout is introduced together with a description of the data communication among the processors.

RT2: real-time ray-tracing for underwater range evaluation

The paper deals with the distributed acoustic localization of teams of autonomous underwater vehicles (AUVs) and proposes a novel algorithm, real-time ray-tracing (RT2), for evaluating the distance between any pair of AUVs in the team. The technique, based on a modified formulation of the non-linear sound-ray propagation laws, allows efficient handling of the distorted and reflected acoustic ray paths. The proposed algorithm can be easily implemented on-board of low-cost AUVs, requiring the presence, on each vehicle, of an acoustic modem and a pair of look-up tables, a-priori built on the basis of the assumed knowledge of the depth-dependent sound velocity profile. On such a basis, every AUV can compute its distance w.r.t. to any other neighbor team member, through time-of-flight measurements and the exchanges of depth information only.

Conformal Visualization for Partially-Immersive Platforms.

Current immersive VR systems such as the CAVE provide an effective platform for the immersive exploration of large 3D data. A major limitation is that in most cases at least one display surface is missing due to space, access or cost constraints. This partially-immersive visualization results in a substantial loss of visual information that may be acceptable for some applications, however it becomes a major obstacle for critical tasks, such as the analysis of medical data. We propose a conformal deformation rendering pipeline for the visualization of datasets on partially-immersive platforms. The angle-preserving conformal mapping approach is used to map the 360°3D view volume to arbitrary display configurations. It has the desirable property of preserving shapes under distortion, which is important for identifying features, especially in medical data. The conformal mapping is used for rasterization, realtime raytracing and volume rendering of the datasets. Since the technique is applied during the rendering, we can construct stereoscopic images from the data, which is usually not true for image-based distortion approaches. We demonstrate the stereo conformal mapping rendering pipeline in the partially-immersive 5-wall Immersive Cabin (IC) for virtual colonoscopy and architectural review.

The design of a texture mapping unit with effective MIP-map level selection for real-time ray tracing

We propose effective texture-mapping hardware for real-time ray tracing. Therefore, we introduce a novel method to select the MIP-map level of texture images, which requires only the total length of the intersected ray and the pre-calculated value. The proposed architecture can support the texture MIP-mapping by integrating simple hardware logic in existing ray-tracing hardware.