While 3D line drawing techniques have become well established in the past decade, most are only suitable for polygonal meshes. This paper presents splatting lines, a unified framework for generating line drawings from various types of 3D models, including point clouds, volumes, and polygonal meshes. In contrast to the existing mesh-based approaches, our method takes a densely sampled point cloud as input. It renders two diffuse shading images using splatting with different parameters and then generates line drawings by subtracting these images. Our point-based approach can be easily extended to polygonal meshes and volumes by an efficient (iso-)surface sampling method. Our method is highly efficient and it does not require any pre-computation. It is also more robust to the mesh tessellation than existing mesh-based techniques. Experimental results indicate the advantages of our method in terms of both performance and quality.

Line drawings are a popular shape depiction technique due to its capability to express meaningful information by ignoring less important or distracting details. Many computer generated line drawing algorithms have been proposed in the past decade, such as suggestive contours, ridge-valley lines, apparent ridges, photic extremum lines, demarcating curves, Laplacian lines, just name a few.

This paper presents Texture Brush, an interactive interface for texturing 3D surfaces. We extend the conventional exponential map to a more general setting, in which the generator can be an arbitrary curve. Based on our extended exponential map, we develop a local parameterization method which naturally supports anisotropic texture mapping. With Texture Brush, the user can easily specify such local parameterization with a free-form stroke on the surface. We also propose a set of intuitive operations which are mainly based on 3D painting metaphor, including texture painting, texture cloning, texture animation design, and texture editing. Compared to the existing surface texturing techniques, our method enables a smoother and more natural work flow so that the user can focus on the design task itself without switching back and forth among different tools or stages. The encouraging experimental results and positive evaluation by artists demonstrate the efficacy of our Texture Brush for interactive texture mapping.

Line drawings are an effective way to convey shapes in a relatively succinct manner by ignoring the less important or distracting details. In the past decade, many promising computer-generated line drawing algorithms have been proposed, which can be roughly classified into two categories: object-space and image-space.

This paper presents a novel object-space line drawing algorithm that can depict shapes with view-dependent feature lines in real time. Strongly inspired by the Laplacian-of-Gaussian (LoG) edge detector in image processing, we define Laplacian lines as the zero-crossing points of the Laplacian of the surface illumination. Compared to other view-dependent feature lines, Laplacian lines are computationally efficient because most expensive computations can be preprocessed. We further extend Laplacian lines to volumetric data and develop the algorithm to compute volumetric Laplacian lines without isosurface extraction. We apply the proposed Laplacian lines to a wide range of real-world models and demonstrate that Laplacian lines are more efficient than the existing computer generated feature lines, and can be used in interactive graphics applications.

This paper presents a novel object-space line drawing algorithm that can depict shape with view dependent feature lines in real-time. Strongly inspired by the Laplacian-of-Gaussian (LoG) edge detector in image processing, we define Laplacian Lines as the zero-crossing points of the Laplacian of the surface illumination. Compared to other view dependent features, Laplacian lines are computationally efficient because most expensive computations can be pre-processed. Thus, Laplacian lines are very promising for interactively illustrating large-scale models.

Abstract We present a data‐driven approach that synthesizes tree animations from a set of pre‐computed motion data. Our approach improves previous motion synthesis algorithms for character animation in several aspects. We first introduce a simple yet effective sampling scheme to generate a rich and reusable motion database for each tree model. We also propose a novel technique to generate a fine set of transitions that are uniformly distributed in the motion database. The transition lengths are adaptively determined according to the similarity of the transiting frame pairs. In the runtime, we employ a greedy searching algorithm to synthesize smooth tree animations under an adjustable wind condition. Experimental results show that our approach achieves comparable quality to physically based methods, while in orders of magnitude faster performance. Copyright © 2007 John Wiley & Sons, Ltd.

Abstract We propose an efficient approach for authoring dynamic and realistic waterfall scenes based on an acquired video sequence. Traditional video based techniques generate new images by synthesizing 2D samples, i.e., texture sprites chosen from a video sequence. However, they are limited to one fixed viewpoint and cannot provide arbitrary walkthrough into 3D scenes. Our approach extends this scheme by synthesizing dynamic 2D texture sprites and projecting them into 3D space. We first generate a set of basis texture sprites, which capture the representative appearance and motions of waterfall scenes contained in the video sequence. To model the shape and motion of a new waterfall scene, we interactively construct a set of flow lines taking account of physical principles. Along each flow line, the basis texture sprites are manipulated and animated dynamically, yielding a sequence of dynamic texture sprites in 3D space. These texture sprites are displayed using the point splatting technique, which can be accelerated efficiently by graphics hardware. By choosing varied basis texture sprites, waterfall scenes with different appearance and shapes can be conveniently simulated. The experimental results demonstrate that our approach achieves realistic effects and real‐time frame rates on consumer PC platforms. Copyright © 2006 John Wiley & Sons, Ltd.