Abstract We propose Specular Manifold Bisection Sampling (SMBS), an improved version of Specular Manifold Sampling (SMS) [ZGJ20]. SMBS is inspired by the small and large mutations in Metropolis Light Transport (MLT) [VG97]. While the Jacobian Matrix of the original SMS method performs well in local convergence (the small mutation), it might fail to find a valid manifold path when the ray deviates too much from the light or bounces from a complex surface. Our proposed SMBS method adds a large mutation step to avoid such a problematic convergence to the local minimum. The results show SMBS can find valid manifold paths in fewer iterations and also find more valid manifold paths. In scenes with complex reflective or refractive surfaces, our method achieves nearly twice or more improvement when measured in manifold walk success rate (SR) and root mean square error (RMSE).

Grass, lawn, and meadow are common features of outdoor scenes. However, animating the grass motion under the influence of wind could be a daunting task especially if the subtle variations between grass blades are considered. Collectively, those variations of individual grass blades may produce interesting phenomena, such as the eye catching wave-like motion of a meadow. In this work, we develop a framework that simulates the grass dynamics under a plausible wind field. We first test it with a small bunch of grass blades (Figure 1) and validate it with the motion of real-world grass. By utilizing the tessellation shaders and geometry shaders of modern GPUs, we make our grass model as efficient as possible so that it scales well to a large meadow, which is also exposed to a plausible wind field simulation. As a result, our grass simulation runs in real time for meadow scenes consisting of hundreds of thousands of grass blades, and produces convincing wave-like motions when the wind blows over the meadow.

We present an interactive system for ink splattering, a form of abstract arts that artists drip or pour inks onto the canvas. The user interface and interactive methods are designed to be analogous to the artsitic techniques of ink splattering in real world so that digital artists can easily create the vibrant patterns of splattering ink, which are otherwise difficult to achieve in image editing software. The core of our system is a novel three-stage ink splattering framework that simulates the physical-based interaction of ink with different mediums including brush heads, air and paper. We implemented the physical engine using CUDA and the whole simulation process runs in real-time.

Abstract This paper presents an interactive system for ink splattering, a form of abstract art that artists splat ink onto the canvas. The default input device of our system is a pressure‐sensitive 2D stylus, the most common sketching tool for digital artists, and we propose two interaction mode:ink‐flicking modeandink‐dripping mode, that are designed to be analogous to the artistic techniques of ink splattering in real world. The core of our ink splattering system is a novel three‐stage ink splattering framework that simulates the physics‐based interaction of ink with different mediums including brush heads, air and paper. We have implemented the physical engine in CUDA and the whole simulation process runs at interactive speed.

Abstract We introduce a screen‐space statistical filtering method for real‐time rendering with global illumination. It is inspired by statistical filtering proposed by Meyer et al. to reduce the noise in global illumination over a period of time by estimating the principal components from all rendered frames. Our work extends their method to achieve nearly real‐time performance on modern GPUs. More specifically, our method employs the candid covariance‐free incremental PCA to overcome several limitations of the original algorithm by Meyer et al., such as its high computational cost and memory usage that hinders its implementation on GPUs. By combining the reprojection and per‐pixel weighting techniques, our method handles the view changes and object movement in dynamic scenes as well.

Abstract We present a facial motion retargeting method that enables the control of a blendshape rig according to marker‐based motion capture data. The main purpose of the proposed technique is to allow a blendshape rig to create facial expressions, which conforms best to the current motion capture input, regardless the underlying blendshape poses. In other words, even though all of the blendshape poses may comprise symmetrical facial expressions only, our method is still able to create asymmetrical expressions without physically splitting any of them into more local blendshape poses. An automatic segmentation technique based on the analysis of facial motion is introduced to create facial regions for local retargeting. We also show that it is possible to blend normal maps for rendering in the same framework. Rendering with the blended normal map significantly improves surface appearance and details. Copyright © 2011 John Wiley & Sons, Ltd.

Revision control is a vital component of digital project management and has been widely deployed for text files. Binary files, on the other hand, have received relatively less attention. This can be inconvenient for graphics applications that use a significant amount of binary data, such as images, videos, meshes, and animations. Existing strategies such as storing whole files for individual revisions or simple binary deltas could consume significant storage and obscure vital semantic information. We present a nonlinear revision control system for images, designed with the common digital editing and sketching workflows in mind. We use DAG (directed acyclic graph) as the core structure, with DAG nodes representing editing operations and DAG edges the corresponding spatial, temporal and semantic relationships. We visualize our DAG in RevG (revision graph), which provides not only as a meaningful display of the revision history but also an intuitive interface for common revision control operations such as review, replay, diff, addition, branching, merging, and conflict resolving. Beyond revision control, our system also facilitates artistic creation processes in common image editing and digital painting workflows. We have built a prototype system upon GIMP, an open source image editor, and demonstrate its effectiveness through formative user study and comparisons with alternative revision control systems.

No abstract available.

Abstract We present metalights, a novel Virtual Point Light (VPL) encapsulating structure which enhances classic interleaved shading by improving VPL sampling, based on few initial screen space samples to estimate VPL contribution to current view. Our method leads to important noise variance reduction in the final picture by only adding a small fraction of computation. The implementation is straight‐forward and well adapted to both CPU and GPU‐based engines. We also present different image‐space assignment schemes for the VPL subsets to break the regularity of the noise pattern or to adapt it to simple antialiasing.

For effectively rendering surface details, many texture-based methods such as normal mapping and displacement mapping were used to model detailed structures on a surface. Although self-shadow can be achieved by those techniques, most of them support hard shadow or ad-hoc approximation of soft-shadow for the self-shadow effects. In this paper, we present a simple method to render soft shadow casted by area lights on displacement mapped surfaces in real-time rendering applications such as 3D game engines. Our method first computes a visibility cone map, which stores the average visible ratio of each texel toward a certain direction. Then, during the rendering, the intensity of each pixel on the texture mapped surfaces can be calculated from the overlap between the projected lighting area and the projected visible cone.

Abstract Silhouette is a key feature that distinguishes displacement mapping from normal mapping. However the silhouette rendering in the GPU implementation of displacement mapping (which is often called inversed displacement mapping) is tricky. Previous approaches rely mostly on construction of additional extruding prism‐like geometry, which slows down the rendering significantly. In this paper, we proposed a method for solving the silhouette rendering problem in inverse displace mapping without using any extruding prism‐like geometry. At each step of intersection finding, we continuously bends the viewing ray according to the current local tangent space associated with the surface. Thus, it allows mapping a displacement map onto an arbitrary curved surface with more accurate silhouette. While our method is simple, it offers surprisingly good results over Curved Relief Map (CRM) [ OP05 ] in many difficult or degenerated cases.

We present efficient algorithms for real-time rendering of ocean using the newest features of programmable graphics processors (GPU). It differs from previous works in three aspects: adaptive GPU-based ocean surface tessellation, sophisticated optical effects for shallow water, and spray dynamics for oscillating waves. Our tessellation scheme not only offers easier level-of-detail (LOD) control but also avoids the loading of vertex attributes from CPU to GPU at each frame. The object-space wave sampling approach allows us to produce sophisticated optical effects for shallow water and implement a state-preserving particle system for simulating spray motions interactively

This paper presents a new technique for rendering bidirectional texture functions (BTFs) at different levels of detail (LODs). Our method first decomposes each BTF image into multiple subbands with a Laplacian pyramid. Each vector of Laplacian coefficients of a texel at the same level is regarded as a Laplacian bidirectional reflectance distribution function (BRDF). These vectors are then further compressed by applying principal components analysis (PCA). At the rendering stage, the LOD parameter for each pixel is calculated according to the distance from the viewpoint to the surface. Our rendering algorithm uses this parameter to determine how many levels of BTF Laplacian pyramid are required for rendering. Under the same sampling resolution, a BTF gradually transits to a BRDF as the camera moves away from the surface. Our method precomputes this transition and uses it for multiresolution BTF rendering. Our Laplacian pyramid representation allows real-time anti-aliased rendering of BTFs using graphics hardware. In addition to provide visually satisfactory multiresolution rendering for BTFs, our method has a comparable compression rate to the available single-resolution BTF compression techniques.

In this paper, we propose an appearance representation for general complex materials which can be applied in real-time rendering framework. By combining a single parametric shading function (such as the Phong model) and the proposed spatial-varying residual function (SRF), this representation can recover the appearance of complex materials with little loss of visual fidelity. The difference between the real data and the parametric shading is directly fitted by a specific function for easy reconstruction. It is simple, flexible and easy to be implemented on programmable graphics hardware. Experiments show that the mean square error (MSE) between the reconstructed appearance and real photographs is less than 5%.

Article LDI tree: a hierarchical representation for image-based rendering Share on Authors: Chun-Fa Chang University of North Carolina at Chapel Hill University of North Carolina at Chapel HillView Profile , Gary Bishop University of North Carolina at Chapel Hill University of North Carolina at Chapel HillView Profile , Anselmo Lastra University of North Carolina at Chapel Hill University of North Carolina at Chapel HillView Profile Authors Info & Claims SIGGRAPH '99: Proceedings of the 26th annual conference on Computer graphics and interactive techniquesJuly 1999 Pages 291–298https://doi.org/10.1145/311535.311571Online:01 July 1999Publication History 95citation1,161DownloadsMetricsTotal Citations95Total Downloads1,161Last 12 Months22Last 6 weeks2 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access