Rasterization hardware provides interactive frame rates for rendering dynamic scenes, but lacks the ability of ray tracing required for efficient global illumination simulation. Existing ray tracing based methods yield high quality renderings but are far too slow for interactive use. We present a new parallel global illumination algorithm that perfectly scales, has minimal preprocessing and communication overhead, applies highly efficient sampling techniques based on randomized quasi-Monte Carlo integration, and benefits from a fast parallel ray tracing implementation by shooting coherent groups of rays. Thus a performance is achieved that allows for applying arbitrary changes to the scene, while simulating global illumination including shadows from area light sources, indirect illumination, specular effects, and caustics at interactive frame rates. Ceasing interaction rapidly provides high quality renderings.

We introduce the notion of image-driven simplification, a framework that uses images to decide which portions of a model to simplify. This is a departure from approaches that make polygonal simplification decisions based on geometry. As with many methods, we use the edge collapse operator to make incremental changes to a model. Unique to our approach, however, is the use of comparisons between images of the original model against those of a simplified model to determine the cost of an edge collapse. We use common graphics rendering hardware to accelerate the creation of the required images. As expected, this method produces models that are close to the original model according to image differences. Perhaps more surprising, however, is that the method yields models that have high geometric fidelity as well. Our approach also solves the quandary of how to weight the geometric distance versus appearance properties such as normals, color and texture. All of these tradeoffs are ba...

with shadows and refractions), a Conference room (5.5 fps, without shadows), reflective and refractive Spheres-RT in an office (4.5 fps), and UT2003 a scene from a current computer game (7.5 fps, precomputed illumination). 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.

encodes separated clusters generated by our motion decomposition algorithm. All animations combine flexible non-affine body motion from skinning, and other deformations. They can be ray traced with 5 to 15 frames per second at 1024 2 pixels on a single CPU. Though ray tracing has recently become interactive, its high precomputation time for building spatial indices usually limits its applications to walkthroughs of static scenes. This is a major limitation, as most applications demand support for dynamically animated models. In this paper, we present a new approach to ray trace a special but important class of dynamic scenes, namely models whose connectivity does not change over time and for which all possible poses are known in advance. We support these kinds of models by introducing two new concepts: motion decomposition, and fuzzy kd-trees. We analyze the animation and break the model down into submeshes with similar motion. For each of these submeshes and for every time step, we calculate a best affine transformation through a least square approach. Any residual motion is then captured in a single “fuzzy kd-tree ” for the entire animation. Together, these techniques allow for ray tracing animations without rebuilding the spatial index structures for the submeshes, resulting in interactive frame rates of 5 to 15 fps even on a single CPU. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Ray tracing I.3.6 [Methodology and Techniques]: Graphics data structures and data types

Global illumination algorithms have traditionally been very time consuming and were only suitable for off-line computations. Recent research in realtime ray tracing has improved global illumination performance to allow for illumination updates at interactive rates. However, both the traditional off-line and the new interactive systems show significant limitations when dealing with realistically complex scenes containing millions of surfaces, thousands of light sources, and a high degree of occlusion. In this paper,

Several techniques for acceleration of ray tracing parametric surfaces are presented. Some of these are entirely new to ray tracing, while others are improvements of previously known techniques. First a uniform spatial subdivision scheme is adapted to parametric surfaces. A new space- and time-efficient algorithm for finding ray-surface intersections is introduced. It combines numerical and subdivision techniques, thus allowing utilization of ray-coherence and greatly reducing the average ray-surface intersection time. Non-scanline sampling orders of the image plane are proposed that facilitate utilization of coherence. Finally, a method to handle reflected, refracted, and shadow rays in a more efficient manner is described. Results of timing tests indicating the efficiency of these techniques for various environments are presented.

Recently developed interactive ray tracing systems combine the high-performance of todays CPUs with new algorithms and implementations to achieve a flexible and highperformance rendering system offering high-quality, interactive 3D graphics. However, due to its history in off-line rendering, interactive ray tracing has been limited to static scenes and simple walkthroughs. However, in order to become truly interactive ray tracing must support dynamic scenes efficiently.

Recursive ray tracing is a powerful rendering technique used to compute realistic images by simulating the global light transport in a scene. Algorithmic improvements and FPGA-based hardware implementations of ray tracing have demonstrated realtime performance but hardware that achieves performance levels comparable to commodity rasterization graphics chips is still not available. This paper describes the architecture and ASIC implementations of the DRPU design (Dynamic Ray Processing Unit) that closes this performance gap. The DRPU supports fully programmable shading and most kinds of dynamic scenes and thus provides similar capabilities as current GPUs. It achieves high efficiency due to SIMD processing of floating point vectors, massive multithreading, synchronous execution of packets of threads, and careful management of caches for scene data. To support dynamic scenes B-KD trees are used as spatial index structures that are processed by a custom traversal and intersection unit and modified by an Update Processor on scene changes. The DRPU architecture is specified as a high-level structural description in a functional language and mapped to both FPGA and ASIC implementations. Our FPGA prototype clocked at 66 MHz achieves higher ray tracing performance than CPU-based ray tracers even on a modern multi-GHz CPU. We provide performance results for two 130nm ASIC versions and estimate what performance would be using a 90nm CMOS process. For a 90nm version with a 196mm 2 die we conservatively estimate clock rates of 400 MHz and ray tracing performance of 80 to 290 fps at 1024x768 resolution in our test scenes. This estimated performance is 70 times faster than what is achievable with standard multi-GHz desktop CPUs.

Abstract — Focusing in the advantages and drawbacks on the FPGA implementations vs. ASIC and pure software, this paper surveys the development of computer graphics. We start with the description of the theoretical problems related to computer graphics. Consequently, we present the most relevant industrial and academic solutions categorizing them from the point of view of their contribution in the speed up of Graphics Pipeline. Finally we introduce the MOLEN reconfigurable computer paradigm project and how the reconfigurable organizations based on this architecture could help in the establishment of an integral solution for computer graphics processing.

Our research team is developing a computer construction game called VirtualPrismaker based on the physical game Prismaker . We have had to deal with all typical and essential features of any realistic 3D modelling and animation environment. A first aim in these kinds of environments is to provide an easy way to manipulate the game pieces. The need to use standard input devices in a natural manner has guided us to limit movement freedom. This imposed limitation allows the pieces to be easily assembled. As we try to achieve a realistic simulation, collision handling and shadow casting are two more problems found up to date. In this paper we comment some lacks of the Java 3D application programming interface in this context, and we propose our solutions. Collision handling is faced by using a 3D grid that stores the position of all objects of the virtual playground. Shadow casting is simulated by drawing polygons according to a single light source and the environmental light and using the associated 3D grid position information.