Ray Tracing Of Dynamic Scenes Research Articles

A fast ray tracing algorithm based on a hybrid structure

This paper proposes a new group-based accelerating structure called hybrid structure for the ray tracing of dynamic scenes, whose main advantage is that we can choose a suitable local accelerating structure for each object in the scene. In the hybrid structure, the objects in the scene are organized into a hierarchical bounding volume structure by surface area heuristic (SAH) cost model with each object group node including only one object, and a local accelerating structure is constructed for each object. For a hybrid structure, a scene is divided into static part and dynamic part by the movement, and only dynamic part is updated in each frame. In addition, we design an efficient storage format according to the graphics processing unit (GPU) storage characteristics, which makes it easy to realize the parallel ray tracing on GPU. Experimental results show that the hybrid structure is efficient to deal with the dynamic scene including different kinds of objects, and it can be easily integrated into parallel application systems.

Fast BVH construction and refit for ray tracing of dynamic scenes

As the complexity of virtual environments increases, it becomes a critical issue to ray tracing of dynamic scenes interactively. In this paper, we propose an effective method to address this issue. Firstly, we improve the Surface Area Heuristics (SAH) based bounding volume hierarchies (BVHs) construction algorithm and present a sub-interval search criterion for predicting the optimal split plane position. Compared with the standard SAH approach, our algorithm is much faster but has a little quality degradation. Secondly, we present two new BVH refitting operations, which could run fast and obtain considerable quality of BVHs. The two operations are general and applicable to complex and dynamic scenes including a wide range of deformation. Lastly we use multithread to handle the dynamic scenes during animation, one thread for BVHs rebuilding asynchronously, the others for BVHs refitting and ray tracing. The results of this experiment show that our method is effective. Compared with the previous works, it obtains higher and smoother frame rate.

GkDtree: A group-based parallel update kd-tree for interactive ray tracing

This paper proposes a new group-based acceleration data structure called gkDtree for interactive ray tracing of dynamic scenes. The main idea of the gkDtree is to construct the acceleration structure with a multi-level hierarchy, and to integrate a parallelization approach to result in a faster update and a more efficient tree traversal. A gkDtree can be viewed as a set of kd-trees, each of which is a local acceleration structure corresponding to a group. For a gkDtree, a scene is divided into several groups based on a scene graph. The local acceleration structure of each group involving only dynamic primitives is rebuilt. To achieve higher parallelization, dependencies among groups in different levels are removed before rebuilding occurs in parallel. To enhance the scalability of parallelization, a simple and fast load-balancing scheme is introduced. Furthermore, we apply a variety of accurate SAH (surface area heuristic) algorithms into tree generation for both static and dynamic groups. The experimental results show that a gkDtree has a real-time update performance. It has an update performance that is up to 166 times faster than a kd-tree for our test scenes in a six-core hardware system environment. Furthermore, the results also show that tree traversal performance of a gkDtree is competitive with that of a kd-tree.

Two‐Level Grids for Ray Tracing on GPUs

AbstractWe investigate the use of two‐level nested grids as acceleration structure for ray tracing of dynamic scenes. We propose a massively parallel, sort‐based construction algorithm and show that the two‐level grid is one of the structures that is fastest to construct on modern graphics processors. The structure handles non‐uniform primitive distributions more robustly than the uniform grid and its traversal performance is comparable to those of other high quality acceleration structures used for dynamic scenes. We propose a cost model to determine the grid resolution and improve SIMD utilization during ray‐triangle intersection by employing a hybrid packetization strategy. The build times and ray traversal acceleration provide overall rendering performance superior to previous approaches for real time rendering of animated scenes on GPUs.

Ray Tracing of Dynamic Scenes by Managing Empty Regions in Adaptive Boxes

This paper presents a new ray-tracing technique to efficiently speed up ray traversal in empty regions. It first produces grid cells in a new method,and then aggregates empty cells adaptively into fewer empty boxes,so that much acceleration can be obtained by reducing computation on ray going through empty regions. The new acceleration structure can be constructed in O(n) time,and its storage complexity is also O(n). By such a structure,rays can be traced in O(log n) time,similar to ray tracing via a kd-tree . When this structure is integrated with existing acceleration structures,large dynamic scenes can be efficiently rendered. For instance,a dynamic scene with multiple buddha models in up to 6G triangles can be interactively rendered in high photorealism on a common PC,where rays are traced individually and second rays are also computed.

Fast, parallel, and asynchronous construction of BVHs for ray tracing animated scenes

Recent developments have produced several techniques for interactive ray tracing of dynamic scenes. In particular, bounding volume hierarchies (BVHs) are efficient acceleration structures that handle complex triangle distributions and can accommodate deformable scenes by updating (refitting) the bounding primitive without restructuring the entire tree. Unfortunately, updating only the bounding primitive can result in a degradation of the quality of the BVH, and in some scenes will result in a dramatic deterioration of rendering performance. In this paper, we present three different orthogonal techniques to avoid that deterioration: (a) quickly rebuilding the BVH using a fast, binning-based approach; (b) a parallel variant of that build to better exploit the multi-core architecture of modern CPUs; (c) asynchronously rebuilding the BVH concurrently with rendering and animation, allowing it to scale to even larger models by stretching the (parallel) BVH build over one or more frames. Our approach is particularly targeted toward future many-core architectures, and allows for flexibly allocating how many cores are used for rebuilding vs. how many are used for rendering.

Highly Parallel Fast KD‐tree Construction for Interactive Ray Tracing of Dynamic Scenes

Abstract We present a highly parallel, linearly scalable technique of kd‐tree construction for ray tracing of dynamic geometry. We use conventional kd‐tree compatible with the high performing algorithms such as MLRTA or frustum tracing. Proposed technique offers exceptional construction speed maintaining reasonable kd‐tree quality for rendering stage. The algorithm builds a kd‐tree from scratch each frame, thus prior knowledge of motion /deformation or motion constraints are not required. We achieve nearly real‐time performance of 7‐12 FPS for models with 200K of dynamic triangles at 1024x1024 resolution with shadows and textures.

RPU

Recursive ray tracing is a simple yet powerful and general approach for accurately computing global light transport and rendering high quality images. While recent algorithmic improvements and optimized parallel software implementations have increased ray tracing performance to realtime levels, no compact and programmable hardware solution has been available yet.This paper describes the architecture and a prototype implementation of a single chip, fully programmable Ray Processing Unit (RPU). It combines the flexibility of general purpose CPUs with the efficiency of current GPUs for data parallel computations. This design allows for realtime ray tracing of dynamic scenes with programmable material, geometry, and illumination shaders.Although, running at only 66 MHz the prototype FPGA implementation already renders images at up to 20 frames per second, which in many cases beats the performance of highly optimized software running on multi-GHz desktop CPUs. The performance and efficiency of the proposed architecture is analyzed using a variety of benchmark scenes.