24-Issue 1
https://diglib.eg.org:443/handle/10.2312/119
Regular Issue2024-03-29T06:35:48ZAcquisition, Synthesis, and Rendering of Bidirectional Texture Functions
https://diglib.eg.org:443/handle/10.2312/CGF.v24i1pp083-109
Acquisition, Synthesis, and Rendering of Bidirectional Texture Functions
Mueller, G.; Meseth, J.; Sattler, M.; Sarlette, R.; Klein, R.
One of the main challenges in computer graphics is still the realistic rendering of complex materials such as fabric or skin. The difficulty arises from the complex meso structure and reflectance behavior defining the unique look-and-feel of a material. A wide class of such realistic materials can be described as 2D-texture under varying light- and view direction, namely, the Bidirectional Texture Function (BTF). Since an easy and general method for modeling BTFs is not available, current research concentrates on image-based methods, which rely on measured BTFs (acquired real-world data) in combination with appropriate synthesis methods. Recent results have shown that this approach greatly improves the visual quality of rendered surfaces and therefore the quality of applications such as virtual prototyping. This state-of-the-art report (STAR) will present the techniques for the main tasks involved in producing photo-realistic renderings using measured BTFs in details.
2005-01-01T00:00:00ZAn Interactive Deformation System for Granular Material
https://diglib.eg.org:443/handle/10.2312/CGF.v24i1pp051-060
An Interactive Deformation System for Granular Material
Onoue, Koichi; Nishita, Tomoyuki
Computer Graphics (CG) animations of natural phenomena are currently widely used for movies and in video games. Granular materials occur widely in nature, and therefore it is necessary that CG animations represent ground surfaces composed of a granular material as well as model deformations when the granular material comes into contact with other physical rigid objects (called solid objects). In this paper, we propose a deformation algorithm for ground surfaces composed of granular material. The deformation algorithm is divided into three steps: (1) detection of the collision between a solid object and the ground surface, (2) displacement of the granular material and (3) erosion of the material at steep slopes. The proposed algorithm can handle solid objects of various shapes, including concave polyhedra by additionally using a layered data structure called the Height Span Map. Furthermore, a texture sliding technique is presented to render the motion of granular materials. In addition, our implementation of the deformation algorithm can be used at interactive frame rates.
2005-01-01T00:00:00ZCollision Detection for Deformable Objects
https://diglib.eg.org:443/handle/10.2312/CGF.v24i1pp061-081
Collision Detection for Deformable Objects
Teschner, M.; Kimmerle, S.; Heidelberger, B.; Zachmann, G.; Raghupathi, L.; Fuhrmann, A.; Cani, M.-P.; Faure, F.; Magnenat-Thalmann, N.; Strasser, W.; Volino, P.
Interactive environments for dynamically deforming objects play an important role in surgery simulation and entertainment technology. These environments require fast deformable models and very efficient collision handling techniques. While collision detection for rigid bodies is well investigated, collision detection for deformable objects introduces additional challenging problems. This paper focuses on these aspects and summarizes recent research in the area of deformable collision detection. Various approaches based on bounding volume hierarchies, distance fields and spatial partitioning are discussed. In addition, image-space techniques and stochastic methods are considered. Applications in cloth modeling and surgical simulation are presented.
2005-01-01T00:00:00ZEfficient Rendering of Local Subsurface Scattering
https://diglib.eg.org:443/handle/10.2312/CGF.v24i1pp041-049
Efficient Rendering of Local Subsurface Scattering
Mertens, Tom; Kautz, Jan; Bekaert, Philippe; Van Reeth, Frank; Seidel, Hans-Peter
A novel approach is presented to efficiently render local subsurface scattering effects. We introduce an importance sampling scheme for a practical subsurface scattering model. It leads to a simple and efficient rendering algorithm, which operates in image space, and which is even amenable for implementation on graphics hardware. We demonstrate the applicability of our technique to the problem of skin rendering, for which the subsurface transport of light typically remains local. Our implementation shows that plausible images can be rendered interactively using hardware acceleration.
2005-01-01T00:00:00Z