GRAPP 2015 Abstracts
Area 1 - Geometry and Modeling
Full Papers| Paper Nr: | 3 |
| Title: | A Parametric Space Approach to the Computation of Multi-scale Geometric Features |
| Authors: | Anthousis Andreadis, Georgios Papaioannou and Pavlos Mavridis |
| Abstract: | In this paper we present a novel generic method for the fast and accurate computation of geometric features at multiple scales. The presented method works on arbitrarily complex models and operates in the parametric space. The majority of the existing methods compute local features directly on the geometric representation of the model. Our approach decouples the computational complexity from the underlying geometry and in contrast to other parametric space methods, it is not restricted to a specific feature or parameterization of the surface. We show that the method performs accurately and at interactive rates, even for large feature areas of support, rendering the method suitable for animated shapes. |
| Paper Nr: | 14 |
| Title: | Improved Representation of Dependencies in Feature-based Parametric CAD Models using Acyclic Digraphs |
| Authors: | Jorge D. Camba and Manuel Contero |
| Abstract: | In an engineering design context, the process of modeling complex 3D parts with feature-based parametric software systems often produces a large number of dependencies between geometric features that are difficult to manage. The resulting network of feature interdependencies can be understood as an alternative representation of the CAD model that can help identify the most important aspects of the geometry, its critical features, and understand the overall complexity and interconnectedness of the model. Being able to visualize and process this information efficiently can significantly enhance design activities and facilitate model reuse, which can ultimately lead to cost and time savings, and better quality models. In this paper, we identify some of the simplifications and elements that are overlooked by current representation techniques and describe the negative consequences of not taking these elements into consideration. We describe a new method and a software solution to generate a simplified, intuitive, and more accurate visualization of a parametric model as an acyclic digraph. Finally, to validate our approach, the proposed representation is compared to existing techniques using a group of CAD models. |
| Paper Nr: | 29 |
| Title: | Inverse Light Design for High-occlusion Environments |
| Authors: | Anastasios Gkaravelis, Georgios Papaioannou and Konstantinos Kalampokis |
| Abstract: | Lighting design is a demanding but very important task in computer cinematography, games and architectural design. Computer-assisted lighting design aims at providing the designers with tools to describe the desired outcome and derive a suitable lighting configuration to match their goal. In this paper, we present an automatic approach to the inverse light source emittance and positioning problem, based on a layered linear / non-linear optimization strategy and the introduction of a special light source indexing according to the compatibility of each individual luminary position with the desired illumination. Our approach is independent of a particular light transport model and can quickly converge to an appropriate and plausible light configuration that approximates the desired illumination and can handle environments with high occlusion. |
| Paper Nr: | 36 |
| Title: | Synthesizing Realistic Shadows with Bumpy Surface and Object Model Estimated by Shadows in Single Image |
| Authors: | Jung-Hsuan Wu and Suguru Saito |
| Abstract: | Shadows play an important role in the human perception of 3D geometry in photographs, and properly synthesized shadows produce a realistic rendering result. Shadows, especially hard shadows, define powerful constraints between a light source, occluders, and the surfaces onto which shadows are cast. We aim to create a pseudo 3D scene in which the light produces shadows that are the same as those in the input image by taking the shadow constraints into account. Our method requires only a few user annotations and an input image, with the objects and their cast-shadows segmented in advance. The segmentation and the user annotations are used to create a shadow-free texture and a 3D scene, and users can then interactively edit the image by moving the objects and changing the lighting. Our system produces realistic shadows in real-time while enabling interactive editing. |
| Paper Nr: | 38 |
| Title: | Volumetric Quasi-conformal Mappings - Quasi-conformal Mappings for Volume Deformation with Applications to Geometric Modeling |
| Authors: | Alexander Naitsat, Emil Saucan and Yehoshua Y. Zeevi |
| Abstract: | Due to intrinsic differences between surfaces and higher dimensional objects, some important results regarding surfaces can not be extended to volumetric domains. Most significantly, there exist no conformal volumetric maps apart from Möbius transformations. Although it is sometime stated explicitly, it is often overlooked that existing methods of volume parameterization produce only quasi-conformal maps, which may be “far from conformality”. We therefore introduce methods for assessing the extent of the local and global volumetric deformation by means of the amount of conformal distortion produced. To this end we first illustrate basic three-dimensional quasi-conformal deformations that are produced by parameterization techniques, and highlight theoretical issues associated with spatial quasi-conformal mappings, and the relation that exists between the geometry of the domain and conformal distortion. |
| Paper Nr: | 44 |
| Title: | Towards a Fully Automatic Markerless Motion Analysis System for the Estimation of Body Joint Kinematics with Application to Sport Analysis |
| Authors: | A. El-Sallam, M. Bennamoun, K. Honda, A. Lyttle and J. Alderson |
| Abstract: | We present a complete markerless motion analysis system for the estimation of human body joint kinematics (JK) in sports. The system works in two phases, an offline phase in which a reference 3D scan (model) of the athlete is acquired. A skeleton consisting of a number of articulated joints is then fitted to the model based on anatomical data. In the online phase, a number of video cameras are utilized to capture the athlete motion from different viewpoints. In order to reconstruct the 3D motion of the athlete, a method is developed to estimate the intrinsic and the extrinsic parameters of all cameras. Synchronized videos are then captured of the athlete while performing an action then a kernel density estimator based background segmentation algorithm is applied to extract the silhouettes of the athlete in each video which are then reprojected to their 3D source to reconstruct an estimate of the body shape (visual hull). To estimate the JK, constrained optimization techniques are then used to extract information from the shape and the skeleton of the reconstructed VH. This includes a number of geometrically-driven cost functions driven by mathematical and physical constraints of the human body to align and deform the reference 3D model to the shape of the VH. Unlike existing pose estimation approaches where a reference pose with labeled body parts are used to initialize the pose estimation process, our approach identifies the the body shape and parts automatically and without any assumptions of its temporal continuity when dealing with unrelated frames which is a very challenging task due to the high dimensionality of the pose space. The proposed system modules are tested with real examples and achieved a promising results. |
| Paper Nr: | 52 |
| Title: | Integrated Modeling of Road Environments for Driving Simulation |
| Authors: | Carlos Campos, João Miguel Leitão and António Fernando Coelho |
| Abstract: | Virtual environments for driving simulations aimed to scientific purposes require three-dimensional road models that must obey to detailed standards of specification and realism. The creation of road models with this level of quality requires previous definition of the road networks and the road paths. Each road path is usually obtained through the dedicated work of roadway design specialists, resulting in a long time consuming process. The driving simulation for scientific purposes also requires a semantic description of all elements within the environment in order to provide the parameterization of actors during the simulation and the production of simulation reports. This paper presents a methodology to automatically generate road environments suitable to the implementation of driving simulation experiences. This methodology integrates every required step for modelling road environments, from the determination of interchanges nodes to the generation of the geometric and the semantic models. The human supervisor can interact with the model generation process at any stage, in order to meet every specific requirement of the experimental work. The proposed methodology reduces workload involved in the initial specification of the road network and significantly reduces the use of specialists for preparing the road paths of all roadways. The generated semantic description allows procedural placing of actors in the simulated environment. The models are suitable for conducting scientific work in a driving simulator. |
| Paper Nr: | 81 |
| Title: | PGP2X: Principal Geometric Primitives Parameters Extraction |
| Authors: | Zahra Toony, Denis Laurendeau and Christian Gagné |
| Abstract: | In reverse engineering, it is important to extract the 3D geometric primitives that compose an object. It is also important to find the values of the parameters describing each primitive. This paper presents an approach for the estimation of the parameters of geometric primitives once their type is known using 3D information. The primitives of interest are planes, spheres, cylinders, cones, tori and partial instances of the latter four types. The proposed approach extends methods found in the literature for planes, spheres, cylinders and cones and proposes a new method for dealing with tori. The results of the proposed method are compared to approaches found in the literature as well as with ground truth values. The proposed method can be applied to the estimation of parameters of geometric primitives of synthetic CAD models as well as for models of real objects acquired with 3D scanners. |
Short Papers
| Paper Nr: | 5 |
| Title: | Generative Training for 3D-Retrieval |
| Authors: | Harald Grabner, Torsten Ullrich and Dieter W. Fellner |
| Abstract: | A digital library for non-textual, multimedia documents can be defined by its functionality: markup, indexing, and retrieval. For textual documents, the techniques and algorithms to perform these tasks are well studied. For non-textual documents, these tasks are open research questions: How to markup a position on a digitized statue? What is the index of a building? How to search and query for a CAD model? If no additional, textual information is available, current approaches cluster, sort and classify non-textual documents using machine learning techniques, which have a cold start problem: they either need a manually labeled, sufficiently large training set or the (automatic) clustering / classification result may not respect semantic similarity. We solve this problem using procedural modeling techniques, which can generate arbitrary training sets without the need of any “real” data. The retrieval process itself can be performed with any method. In this article we describe the histogram of inverted distances in detail and compare it to salient local visual features method. Both techniques are evaluated using the Princeton Shape Benchmark (Shilane et al., 2004). Furthermore, we improve the retrieval results by diffusion processes. |
| Paper Nr: | 6 |
| Title: | Context-sensitive Filtering of Terrain Data based on Multi Scale Analysis |
| Authors: | Steffen Goebbels and Regina Pohle-Fröhlich |
| Abstract: | This paper addresses triangle count reduction for regular terrain triangulations. Supported by additional information available from cadastre data, non-linear low pass filtering based on wavelet coefficients is applied. The aim is to generate a simplified view of a city model’s terrain so that still landmarks can be easily recognized. Height data, that are not critical for visual impressions, are compressed with lower resolution than height data belonging to landmarks. Results are presented for the German city of Krefeld. |
| Paper Nr: | 43 |
| Title: | A Homotopy Surface Cutting using Paths Crossing in Geodesic Distance |
| Authors: | Anuwat Dechvijankit, Hiroshi Nagahashi and Kota Aoki |
| Abstract: | Topology is a property of surfaces that plays a major role in computer graphics. Processing or analysis between two surfaces generally requires both of them to be in same topology. There are many tools or applications such as parameterization or remeshing that require disk topology surfaces as input. Therefore, it is important to convert any surfaces to be same as a topological disk. The common procedure is to define a graph of edges inside the surface that should be split into two edges and to turn the surface into topological disk. We call it as homotopy cutting. Problems become more difficult when dealing with high genus surfaces such as a torus. Based on a novel method, we present an enhancement method to generate a cut graph in high-genus surface for homotopy cutting. By using geodesic properties of each edge, we can generate equally or more suitable edge-graph than original method while keeping similar performance and stability as original one. |
| Paper Nr: | 53 |
| Title: | Local Changes in Marching Cubes to Generate Less Degenerated Triangles |
| Authors: | Thiago F. Leal, Aruquia B. M. Peixoto, Cassia I. G. Silva, Marcelo de A. Dreux and Carlos A. de Moura |
| Abstract: | The Marching Cubes algorithm is widely used to generate surfaces from implicit functions. It builds a mesh of triangles but many degenerated ones happen to appear among them, which can make the mesh thus built unfit for many applications, like the Finite Element Method. To overcome this undesired behavior our work proposes changes on the triangle generation that are automatically generated by Marching Cubes inside each voxel. We first generate the polygon border inside each voxel that intersects the surface. Each polygon is tested so as to guarantee the need to insert a new vertex inside itself, the triangles being then generated according to each polygon properties in order to guarantee the best ratio between their sides and angles. The resulting triangles inside each voxel exhibit the best possible ratio between their dimensions, thus leading to a better mesh. |
| Paper Nr: | 54 |
| Title: | Point Cloud Structural Parts Extraction based on Segmentation Energy Minimization |
| Authors: | Bruno Cafaro, Iman Azimi, Valsamis Ntouskos, Fiora Pirri and Manuel Ruiz |
| Abstract: | In this work we consider 3D point sets, which in a typical setting represent unorganized point clouds. Segmentation of these point sets requires first to single out structural components of the unknown surface discretely approximated by the point cloud. Structural components, in turn, are surface patches approximating unknown parts of elementary geometric structures, such as planes, ellipsoids, spheres and so on. The approach used is based on level set methods computing the moving front of the surface and tracing the interfaces between different parts of it. Level set methods are widely recognized to be one of the most efficient methods to segment both 2D images and 3D medical images. Level set methods for 3D segmentation have recently received an increasing interest. We contribute by proposing a novel approach for raw point sets. Based on the motion and distance functions of the level set we introduce four energy minimization models, which are used for segmentation, by considering an equal number of distance functions specified by geometric features. Finally we evaluate the proposed algorithm on point sets simulating unorganized point clouds. |
| Paper Nr: | 60 |
| Title: | Reconstruction of Relatively Straight Medium to Long Hair Models using Kinect Sensors |
| Authors: | Chao Sun, Zhongrui Li and Won-Sook Lee |
| Abstract: | Most existing hair capturing methods reconstruct 3D hair models from multi-view stereo based on complex capturing systems composed of many digital cameras and light sources. In this paper, we introduce a novel hair capturing system using consumer RGB-D (Kinect sensors). Our capture system, consisting of three Kinect v2 sensors, is much simpler than previous hair capturing systems. We directly use the 3D point clouds captured by Kinect v2 sensors as the hair volume. Then we adopt a fast and robust image enhancement algorithm to adaptively improve the clarity of the hair strands geometry based on the estimated local strands orientation and frequency from the hair images captured by the Kinect colour sensors. In addition, we introduced a hair strand grow-and-connect algorithm to generate relatively complete hair strands. Furthermore, by projecting the 2D hair strands onto the 3D point clouds, we can obtain the corresponding 3D hair strands. The experimental results indicate that our method can generate plausible 3D models for long, relatively straight hair. |
| Paper Nr: | 64 |
| Title: | Mesh Alignment using Grid based PCA |
| Authors: | David Kaye and Ioannis Ivrissimtzis |
| Abstract: | We present an algorithm for mesh alignment by performing Principal Components Analysis (PCA) on a set of nodes of a regular 3D grid. The use of a 3D lattice external to both inputs increases the robustness of PCA, particularly when dealing with meshes of different and possibly uneven vertex density. The proposed algorithm was tested on meshes that have undergone standard mesh processing operations such as smoothing, simplification and remeshing. In several cases the results indicate an improved robustness compared to performing PCA directly on mesh vertices. |
Posters
| Paper Nr: | 20 |
| Title: | CEFM - A Heuristic Mesh Segmentation Method based on Convexity Estimation and Fast Marching |
| Authors: | Jun Zhang, Zhouhui Lian, Zhenbao Liu and Jianguo Xiao |
| Abstract: | Mesh segmentation is a fundamental way of shape analysis and understanding for 3D mesh models. In this paper, we propose an effective heuristic mesh segmentation algorithm, which is based on concave areas detection and heuristic 2-category classification via fast marching. The algorithm has several merits. First, the boundary between each pair of segments is close to the natural seams of 3D objects. Second, it is robust against pose variations and isometric transformations. Finally, our algorithm decomposes non-rigid 3D models into a set of rigid components in a short period of time and the procedure is fully automatic. Extensive experiments in this paper demonstrate that the proposed method outperforms the state of the art in mesh segmentation. |
| Paper Nr: | 24 |
| Title: | Recent Developments in Skin Deformation for Character Animation |
| Authors: | Shaojun Bian, Lihua You and Jian J. Zhang |
| Abstract: | Achieving realistic skin deformation efficiently is a very important task for character animation. With the development of skin deformation, the efficiency and effectiveness of character modelling and animation have been obviously enhanced. In this paper, we survey the recent literature on skin deformation according to three types of approaches: purely geometric, physics-based, and data driven. Especially we focus on the work since 2009. We review the problems they primarily tackles, the methodologies they applies, and the advantages and disadvantages they have. At last, we discuss directions for future research. |
| Paper Nr: | 46 |
| Title: | Second Degree of Freedom of Elastic Objects - Adjustable Poisson’s Ratio for Mass Spring Models |
| Authors: | Maciej Kot and Hiroshi Nagahashi |
| Abstract: | In this paper, we show how to construct mass spring models for the representation of homogeneous isotropic elastic materials with adjustable Poisson’s ratio. Classical formulation of elasticity on mass spring models leads to the result, that while materials with any value of Young’s modulus can be modeled reliably, only fixed value of Poisson’s ratio is possible. We show how to extend the conventional model to overcome this limitation. |
| Paper Nr: | 63 |
| Title: | Probabilistic Modeling of Real-world Scenes in a Virtual Environment |
| Authors: | Frank Dittrich, Stephan Irgenfried and Heinz Woern |
| Abstract: | In this paper we present an approach for the automated creation of real-world scenes in an virtual environment. Here we focus on human-robot interaction and collaboration in the industrial domain, with corresponding virtual object classes and inter-class constellations. As the basis for the sample generation process, we probabilistically model essential discrete and continuous object parameters, by adapting a generic mixed joint density function to distinct scene classes, in order to capture the specific inter- and intra-class dependencies. To provide a convenient way to assert these object interactions, we use a Bayesian Network for the representation of the density function, where dependencies can directly be modeled by the network layout. For the conditioned and uncertain descriptions of object translations, we use hierarchical Gaussian Mixture Models as geometrical sampling primitives in the 3D space. In our paper, we show how the combination of a Bayesian Network with these sampling primitives can directly be used for the automated collision avoidance of objects, during the sampling process. For the illustration of the applicability and usefulness of our approach, we instantiate the generic and abstract concept using an example with reduced complexity. |
| Paper Nr: | 86 |
| Title: | Two-stage Color Texture Synthesis using the Structure Tensor Field |
| Authors: | Adib Akl, Charles Yaacoub, Marc Donias, Jean-Pierre Da Costa and Christian Germain |
| Abstract: | Since reproducing the realism of the physical word is a major goal for computer graphics, color texture synthesis is important for rendering synthetic images and animations. Most of the existing synthesis techniques provide impressive results in many cases, but fail in difficult situations with large patterns, or with long range directional variations. Based on a previously developed two-stage structure/texture synthesis algorithm where the structure tensor is used to represent the structure layer, an extension to color texture synthesis is proposed. Two different methods are used for the computation of the color structure tensor field. An acceleration method for the proposed algorithm is also presented. Results show that the proposed approach successfully synthesizes the output texture in many situations where traditional algorithms fail to reproduce the exemplar’s patterns and dynamics. These promising results pave the way towards 3D color textures synthesis showing multi-scale patterns. |
| Paper Nr: | 90 |
| Title: | Patch-based Terrain Synthesis |
| Authors: | Leandro Cruz, Luiz Velho, Eric Galin, Adrien Peytavie and Eric Guerin |
| Abstract: | In this paper, we present an intuitive and controllable patch-based technique for terrain synthesis. Our method is based on classical patch-based texture synthesis approaches. It generates a new terrain model by combining patches extracted from a given set of exemplars, providing a control performed by a low frequency guide, a categorization of exemplars, and a map for distributing these categories. Furthermore, we propose criteria to validate the input, some structures to accelerate the patch choice, and a metric based on the process, these structures, and some specificities of the data. |
Area 2 - Rendering
Full Papers| Paper Nr: | 13 |
| Title: | Illumination Model for Two-layer Thin Film Structures |
| Authors: | Fukun Wu and Changwen Zheng |
| Abstract: | To address the problem of visualizing the interference effects of objects with multilayer film structures such as soap bubbles, optical lenses and Morpho butterflies in the physics-based framework, a novel full-spectrum multilayer film interference method is presented. This method applies the multi-beam interference equation to effectively simulate the multiple reflection and transmission inside films, and calculate the composite reflectance and transmittance to model the amplitude and phase variations related to interference. The Fresnel coefficients used for metallic and dielectric films are introduced to explain the absorption of photons due to the film materials, and the microfacet scattering factor is also applied to simulate the complex optical effects such as the isotropic and anisotropic phenomena caused by the roughness of the surface geometry. This method is integrated into the existing ray tracer to further enhance the photorealistically rendering capabilities. The experimental results demonstrate that our method can efficiently model the phase and amplitude information of wave to generate high-quality realistic interference effects. |
| Paper Nr: | 56 |
| Title: | Interactive Rendering and Stylization of Transportation Networks using Distance Fields |
| Authors: | Matthias Trapp, Amir Semmo and Jürgen Döllner |
| Abstract: | Transportation networks, such as streets, railroads or metro systems, constitute primary elements in cartography for reckoning and navigation. In recent years, they have become an increasingly important part of 3D virtual environments for the interactive analysis and communication of complex hierarchical information, for example in routing, logistics optimization, and disaster management. A variety of rendering techniques have been proposed that deal with integrating transportation networks within these environments, but have so far neglected the many challenges of an interactive design process to adapt their spatial and thematic granularity (i.e., level-of-detail and level-of-abstraction) according to a user’s context. This paper presents an efficient real-time rendering technique for the view-dependent rendering of geometrically complex transportation networks within 3D virtual environments. Our technique is based on distance fields using deferred texturing that shifts the design process to the shading stage for real-time stylization. We demonstrate and discuss our approach by means of street networks using cartographic design principles for context-aware stylization, including view-dependent scaling for clutter reduction, contour-lining to provide figure-ground, handling of street crossings via shading-based blending, and task-dependent colorization. Finally, we present potential usage scenarios and applications together with a performance evaluation of our implementation. |
| Paper Nr: | 89 |
| Title: | Interactive Relighting of Virtual Objects under Environment Lighting |
| Authors: | Nick Michiels, Jeroen Put and Philippe Bekaert |
| Abstract: | Current relighting applications often constrain one or several factors of the rendering equation to keep the rendering speed real-time. For example, visibility is often precalculated and animations are not allowed, changes in lighting are limited to simple rotation or the lighting is not very detailed. Other techniques compromise on quality and often coarsely tabulate BRDF functions. In order to solve these problems, some techniques have started to use spherical radial basis functions. However, solving the triple product integral does not guarantee interactivity. In order to dynamically change lighting conditions or alter scene geometry and materials, these three factors need to be converted to the SRBF representation in a fast manner. This paper presents a method to perform the SRBF data construction and rendering in real-time. To support dynamic high-frequency lighting, a multiscale residual transformation algorithm is applied. Area lights are detected through a peak detection algorithm. By using voxel cone tracing and a subsampling scheme, animated geometry casts soft shadows dynamically. We demonstrate the effectiveness of our method with a real-time application. Users can shine with multiple light sources onto a camera and the animated virtual scene is relit accordingly. |
Short Papers
| Paper Nr: | 15 |
| Title: | Automatic Color-to-Gray Conversion for Digital Images in Gradient Domain |
| Authors: | Lu Hao, Jie Feng and Bingfeng Zhou |
| Abstract: | Color-to-grayscale conversion for digital color images is widely used in many applications. In this paper an automatic gradient domain color-to-gray conversion method is described. By enhancing the luminance gradient with a modulated chromatic difference enhancement in CIELAB space, a gradient field is created to construct the resulting grayscale image using a Poisson equation solver. A sign function for the gradient is defined for isoluminance color images to keep correct color ordering. By introducing a structural similarity index measurement (SSIM), the main parameters of the method are automatically optimized in the sense of human vision. Therefore, this method can automatically produce artifact-free and salience-preserving grayscale images that coincide with human perception for the color difference. |
| Paper Nr: | 27 |
| Title: | Geometry Batching using Texture-arrays |
| Authors: | Matthias Trapp and Jürgen Döllner |
| Abstract: | High-quality rendering of 3D virtual environments typically depends on high-quality 3D models with significant geometric complexity and texture data. One major bottleneck for real-time image-synthesis represents the number of state changes, which a specific rendering API has to perform. To improve performance, batching can be used to group and sort geometric primitives into batches to reduce the number of required state changes, whereas the size of the batches determines the number of required draw-calls, and therefore, is critical for rendering performance. For example, in the case of texture atlases, which provide an approach for efficient texture management, the batch size is limited by the efficiency of the texture-packing algorithm and the texture resolution itself. This paper presents a pre-processing approach and rendering technique that overcomes these limitations by further grouping textures or texture atlases and thus enables the creation of larger geometry batches. It is based on texture arrays in combination with an additional indexing schema that is evaluated at run-time using shader programs. This type of texture management is especially suitable for real-time rendering of large-scale texture-rich 3D virtual environments, such as virtual city and landscape models. |
| Paper Nr: | 48 |
| Title: | Accelerated Ray Tracing using R-Trees |
| Authors: | Dirk Feldmann |
| Abstract: | Efficient ray tracing for rendering needs to minimize the number of redundant intersection tests between rays and geometric primitives. Hence, ray tracers usually employ spatial indexes to organize the scene to be rendered. The most popular ones for this purpose are currently kd-trees and bounding volume hierarchies, for they have been found to yield best performances and can be adapted to contemporary GPU architectures. These adaptations usually come along with costs for additional memory or preprocessing and comprise the employment of stackless traversal algorithms. R-trees are height-balanced spatial indexes with a fixed maximum number of children per node and were designed to reduce access to secondary memory. Although these properties make them compelling for GPU ray tracing, they have not been used in this context so far. In this article, we demonstrate how R-trees can accelerate ray tracing and their competitiveness for this task. Our method is based on two traversal schemes that exploit the regularity of R-trees and forgo preprocessing or alterations of the data structure, with the first algorithm being moreover stackless. We evaluate our approach in implementations for CPUs and GPUs and compare its performance to results we obtained by means of kd-trees. |
| Paper Nr: | 68 |
| Title: | An Interactive Visualization System for Huge Architectural Laser Scans |
| Authors: | Thomas Kanzok, Lars Linsen and Paul Rosenthal |
| Abstract: | This paper describes a system for rendering large (billions of points) point clouds using a strict level-of-detail criterion for managing the data out of core. The system is comprised of an in-core data structure for managing the coarse hierarchy, an out-of-core structure for managing the actual data and a multithreaded rendering framework that handles the structure and is responsible for data caching, LOD-calculations, culling, and rendering. We demonstrate the performance of our approach with two real-world datasets (a 1.8 b points outdoor scene and a 360m points indoor scene). |
Posters
| Paper Nr: | 55 |
| Title: | Large-scale Terrain Level of Detail Estimation based on Wavelet Transform |
| Authors: | Sid'Ali Kalem and Assia Kourgli |
| Abstract: | The goal of the following paper is to point out an alternative approach to the adaptive triangulation problem. A new technique of terrain rendering which uses wavelet transform to select appropriate LOD is described. This technique is a region-based multi-resolution approach that partitions the terrain into tiles that can be processed independently. The algorithm organizes the heightmap into a QuadTree of nodes and computes maximum world-space errors for each node. World-space errors are then calculated at preprocess step. As the datasets of realistic terrains are usually huge, we suggest using the multi-resolution wavelet decomposition to localize the position of the maximum world-space error estimated and limit the region of research inside the node. It permits to choose the appropriate resolution of the regular grid that will represent the node at run time. By this way, computation load on the CPU is greatly reduced. |
| Paper Nr: | 69 |
| Title: | Multi-pass Gaussian Contact-hardening Soft Shadows |
| Authors: | Kevin Cherry and Robert Kooima |
| Abstract: | Real-time soft shadows have seen numerous improvements over the years. Post-process blurring of shadow edges are commonly used to hide aliasing artifacts, but in some cases, such as ours, it is used to mimic physical processes. Instead of generating penumbra regions uniformly, we scale key algorithmic components in screen space to allow the penumbra region to grow in accordance with occluder/receiver distance. This form of soft shadowing is known to some as contact-hardening and has been explored in various ways. We present an algorithm that explores three ways of achieving contact-hardening soft shadows. Two of those ways are similar in nature to previous works while the third is a novel approach that utilizes occluder distance as a counter for multiple Gaussian passes. Our main contributions are fast occluder approximation and the use of occluder distance to control the number of Gaussian passes. Multiple Gaussian passes create better results than a single Gaussian pass for several scenes, and we explore various ways of improving the performance of the multi-pass approach. |
Area 3 - Animation and Simulation
Full Papers| Paper Nr: | 28 |
| Title: | A Particle-based Dissolution Model using Chemical Collision Energy |
| Authors: | Min Jiang, Richard Southern and Jian Jun Zhang |
| Abstract: | We propose a new energy-based method for real-time dissolution simulation. A unified particle representation is used for both fluid solvent and solid solute. We derive a novel dissolution model from the collision theory in chemical reactions: physical laws govern the local excitation of solid particles based on the relative motion of the fluid and solid. When the local excitation energy exceeds a user specified threshold (activation energy), the particle will be dislodged from the solid. Unlike previous methods, our model ensures that the dissolution result is independent of solute sampling resolution. We also establish a mathematical relationship between the activation energy, the inter-facial surface area, and the total dissolution time — allowing for accurate artistic control over the global dissolution rate while maintaining the physical plausibility of the simulation. We demonstrate applications of our method using a number of practical examples, including antacid pills dissolving in water and hydraulic erosion of non-homogeneous terrains. Our method is straightforward to incorporate with existing particle-based fluid simulations. |
| Paper Nr: | 58 |
| Title: | Interactive Control of Deformable-object Animations through Control Metaphor Pattern Adherence |
| Authors: | Shane Transue and Min-Hyung Choi |
| Abstract: | In this paper we present an adaptive and intuitive methodology for controlling the localized deformations of physically simulated objects using an intuitive pattern-based control interface. To maximize the interactive component presented in this approach we consolidate existing feedback mechanisms in deformable-body control techniques to provide intuitive editing metaphors for stretching, bending, twisting, and compressing simulated objects. The resulting movements created by these control metaphors are validated using imposed behavior evaluation and the effectiveness of this approach is demonstrated through interactively generated compound movements that introduce complex local deformations of objects in existing physical animations. |
Short Papers
| Paper Nr: | 39 |
| Title: | GPU Ray-traced Collision Detection - Fine Pipeline Reorganization |
| Authors: | François Lehericey, Valérie Gouranton and Bruno Arnaldi |
| Abstract: | Ray-tracing algorithms can be used to render a virtual scene and to detect collisions between objects. Numerous ray-tracing algorithms have been proposed which use data structures optimized for specific cases (rigid objects, deformable objects, etc.). Some solutions try to optimize performance by combining several algorithms to use the most efficient algorithm for each ray. This paper presents a ray-traced collision detection pipeline that improves the performance on a graphicd processing unit (GPU) when several ray-tracing algorithms are used. When combining several ray-tracing algorithms on a GPU, a well-known drawback is thread divergence among work-groups that can cause loss of performance by causing idle threads. In this paper we avoid branch divergence by dividing the ray tracing into three steps with append buffers in between. We also show that prediction can be used to avoid unnecessary synchronizations between the CPU and GPU. Applied to a narrow-phase collision detection algorithm, results show an improvement of performance up to 2.7 times. |
| Paper Nr: | 40 |
| Title: | Self-collision Detection using Sphere Chains |
| Authors: | Francisco A. Madera, Enrique Ayala and Francisco Moo-Mena |
| Abstract: | An algorithm to detect self-collisions in a human object is presented. We proposed to approximate the human object by spheres, which are placed inside the object mesh to fill the correspondent volume. We introduce the concept of sphere chain, a set of joined spheres which contains some regions of the human mesh. The object is approximated by several chains in the preprocessing stage to be prepared for the running stage to perform the collision detection. |
| Paper Nr: | 83 |
| Title: | Interactive Control of Dance Groups Using Kinect |
| Authors: | Asako Soga and Itsuo Yoshida |
| Abstract: | This paper describes a system that can control the CG animation of dance groups in a virtual world by recognizing gestures using Kinect in real time. The system can change the formation of CG dancers by right-arm gestures and their motions by left-arm gestures. Moreover, a virtual camera is controlled by the gestures of both arms. The rotational data of the joints are used to recognize each arm gesture to control the dance groups, and the translational data of the joints are used to control the virtual camera. Since the system recognizes both arm gestures at the same time, users can control two or more objects by a combination of gestures. |
Posters
| Paper Nr: | 19 |
| Title: | Automatic Variable-timing Animation Transition based on Hierarchical Interpolation Method |
| Authors: | Yumeng Wang, Fubo Lang, Zheng Wang and Bo Xu |
| Abstract: | Character animation has been used in many fields, such as film making, virtual reality interaction and video games. Video game needs a large set of character animations for users to trigger. However, it is a complex and tedious work for animators to manufacture all the transition animations between each pair of character animations. In this paper, a novel rapid method is presented to generate transition animation automatically. Firstly, animations in the game animation set are classified. Secondly, the time length during motion interpolation is calculated automatically, which is decided by the angle velocity of character’s joints. The method is called variable timing method. Lastly, by using hierarchical interpolation method, postures interpolate between different animations. The transition animation can be quickly acquired, according with human dynamics. In this way, we can get a natural movement by connecting animations together. Experimental results demonstrate that our method can be effectively and efficiently applied to generate transition animations between various character animations. |
| Paper Nr: | 47 |
| Title: | Dance Motion Segmentation Method based on Choreographic Primitives |
| Authors: | Narumi Okada, Naoya Iwamoto, Tsukasa Fukusato and Shigeo Morishima |
| Abstract: | Data-driven animation using a large human motion database enables the programing of various natural human motions. While the development of a motion capture system allows the acquisition of realistic human motion, segmenting the captured motion into a series of primitive motions for the construction of a motion database is necessary. Although most segmentation methods have focused on periodic motion, e.g., walking and jogging, segmenting non-periodic and asymmetrical motions such as dance performance, remains a challenging problem. In this paper, we present a specialized segmentation approach for human dance motion. Our approach consists of three steps based on the assumption that human dance motion is composed of consecutive choreographic primitives. First, we perform an investigation based on dancer perception to determine segmentation components. After professional dancers have selected segmentation sequences, we use their selected sequences to define rules for the segmentation of choreographic primitives. Finally, the accuracy of our approach is verified by a user-study, and we thereby show that our approach is superior to existing segmentation methods. Through three steps, we demonstrate automatic dance motion synthesis based on the choreographic primitives obtained. |
| Paper Nr: | 57 |
| Title: | Procedural Animation of Human Interaction using Inverse Kinematics and Fuzzy Logic |
| Authors: | Gaetan Deglorie, Koen Samyn, Peter Lambert, Rik Van de Walle and Sofie Van Hoecke |
| Abstract: | Nowadays, animation of human interaction is predominantly modelled statically. Animations are adapted manually to each set of participating characters to ensure visual fidelity. To automate this process, we propose a novel procedural animation technique where character interactions are modelled dynamically with fuzzy logic and compare our technique to conventional inverse kinematics. The ’handshake’ interaction is used as an example interaction, in order to illustrate how basic animation rules are defined, while leaving room for parametrization of character specific properties. Our results show that, although inverse kinematics delivers higher precision in positioning than fuzzy logic, they are dependent on paths describing the motion of the final element in the kinematic chain. Fuzzy logic, on the other hand, is independent of such motion paths and solves towards the target location locally. The presented handshake model using fuzzy logic can serve as a basis for future models for virtual-human interaction. |
| Paper Nr: | 59 |
| Title: | Using Expressive and Talkative Virtual Characters in Social Anxiety Disorder Treatment |
| Authors: | Ana Paula Cláudio, Maria Beatriz Carmo, Augusta Gaspar and Renato Teixeira |
| Abstract: | Social Anxiety affects a significant number of people, limiting their personal and social life. We describe an interactive Virtual Reality approach to the exposure therapy for social anxiety, resorting to virtual characters that exhibit combinations of facial and body expressions controllable in real-time by the therapist. The application described in this paper updates and significantly improves a former version: ameliorating the graphical quality of the virtual characters and providing them with the ability of articulating a set of sentences. The application executes in ordinary computers and it is easily used in counselling and research contexts. Although we have only resorted to free or very low cost 3D models of virtual humans, we adopted strategies to obtain an adequate final quality that we were able to validate with a significant number of observers. Moreover, a set of therapists tested the application and gave positive feedback about its potential effectiveness in Virtual Reality Exposure Therapy. |
| Paper Nr: | 74 |
| Title: | Adaptive Animation Design Method for Virtual Environments |
| Authors: | Cheng Cheng and Louyun Li |
| Abstract: | There is a big gap between the WIMP interface animation design tools and virtual environment (VE) animation design platforms. The current animations in virtual environments lack the capability of adaptation, and adaptive animation design processes are programming based development with a great difficulty. These problems vastly limit the animation applications in virtual environments. This paper aims at putting forward an innovative animation construction strategy and methods to cope with these problems. |
| Paper Nr: | 93 |
| Title: | Virtual Pedicle Screw Insertion Surgical Simulation with Haptic Rendering |
| Authors: | Liu Xiaofang, Wang Qiong, Li Jianying, Qin Jing, Wang Weiming, Liu Lichu, Zhang Xiaojuan and Heng Pheng Ann |
| Abstract: | Due to the surrounding of the vital nerves and aortas, pedicle screw insertion is recognised as one of the most dangerous procedure. An instant, efficient and professional tool is in the extreme shortage for the surgeons’ training. In this paper, we proposed a practical framework for the virtual pedicle screw insertion surgery that can be used in the training system. First, a fast collision detection method was developed to progressively determine the contact area at a frequent iteration. Second, a mechanistic haptic model was proposed to implement the bone drilling force, which is qualified to simulate force changes under various tool geometries, cutting conditions and moving velocities. Third, a simplified deformation method was designed to mimic the formation of the drilling hole. Visual plausibility and time performance could be simultaneously obtained with these methods to satisfy the need of the virtual surgical simulation. |
Area 4 - Interactive Environments
Full Papers| Paper Nr: | 2 |
| Title: | Sketching 2D Vessels and Vascular Diseases with Integrated Blood Flow |
| Authors: | Patrick Saalfeld, Alexandra Baer, Uta Preim, Bernhard Preim and Kai Lawonn |
| Abstract: | In this paper, we present a sketch-based interface, which allows medical doctors to illustrate different vascular diseases and treatment methods as well as fluid behavior. With this sketching interface, we provide the physician with an effective tool to illustrate different medical cases, which is important in the complex field of vascular diseases with respect to patient education. We use techniques from sketch-based interfaces and GPU-based computational fluid dynamics by considering usability aspects. We provide a concept and a prototypical implementation whose usability is tested with quantitative and qualitative methods. Additionally, we interviewed a physician to assess the benefits of the tool with respect to patient education. |
| Paper Nr: | 12 |
| Title: | Solid Geometric Object Reconstruction from Single Line Drawing Image |
| Authors: | Jinxin Zheng, Yongtao Wang and Zhi Tang |
| Abstract: | We present a robust method to reconstruct solid geometric object from single line drawing image taken from the geometric books. Unlike most of the existing methods which require perfect and complete sketches of the line drawings as the inputs, our method directly takes the line drawing images as the inputs and can well handle the incomplete sketches that are automatically produced by our sketch extraction algorithm. The proposed method consists of three major steps as follows: First, the sketch of the input line drawing (i.e., line segments and their intersections) is automatically extracted and further represented as an undirected graph. Second, candidate 3D models from the pre-built 3D model database are found by graph matching. Third, for each candidate 3D model, the model parameters, the rotation and the translation aligning the model with the sketch, are found by optimizing an objective function which is composed of the residuals between the vertices of the sketch and the 2D projections of the candidate model’s vertices, and an optimal reconstruction solution is further selected as the final result. Experimental results show that our method can effectively reconstruct the solid geometric object from single line drawing image. |
| Paper Nr: | 70 |
| Title: | The Influence of Gravity-adapted Target Resizing on Direct Augmented Reality Pointing under Simulated Hypergravity |
| Authors: | Daniela Markov-Vetter, Vanja Zander, Joachim Latsch and Oliver Staadt |
| Abstract: | The performance of Augmented Reality direct object selection coded outside of the human egocentric body frame of reference decreases under short-term altered gravity. Therefore adequate countermeasures are required. This paper presents the results of a proof-of-concept (POC) study to investigate the impact of simulated hypergravity on the size and distance of a given target. The POC study is divided in a case study and a user study, whereby hypergravity was induced by a long-arm human centrifuge and additional arm weighting. For gravity-dependent resizing and –positioning we used the Hooke’s law that resulted in two techniques of target deformation (compression, elongation) and compared both methods with normal sized targets. Besides common metrics to measure the performance, we additionally evaluated the physiological strain by the heart rate variability and the speed-accuracy tradeoff of the resizing techniques according to Fitts’ law. The study showed that the online adaption of the present gravity load to targets' size and distance influences the performance of direct AR direct pointing. The results revealed that the pointing performance benefits from elongation target deformation by increased target sizes and distances. |
Short Papers
| Paper Nr: | 91 |
| Title: | NARI: Natural Augmented Reality Interface - Interaction Challenges for AR Applications |
| Authors: | Rui Nóbrega, Diogo Cabral, Giulio Jacucci and António Coelho |
| Abstract: | Following the proliferation of Augmented Reality technologies and applications in mobile devices it is becoming clear that AR techniques have matured and are ready to be used for large audiences. This poses several new multimedia interaction and usability problems that need to be identified and studied. AR problems are no longer exclusively about rendering superimposed virtual geometry or finding ways of performing GPS or computer vision registration. It is important to understand how to keep users engaged with AR and in what occasions it is suitable to use it. Additionally how should graphical user interfaces be designed so that the user can interact with AR elements while pointing a mobile device to a specific real world area? Finally what is limiting AR applications from reaching an even broader acceptance and usage level? This position paper identifies several interaction problems in today’s multimedia AR applications, raising several pressing issues and proposes several research directions. |
| Paper Nr: | 92 |
| Title: | Visualization of Enrollment Data using Chord Diagrams |
| Authors: | Laia Blasco-Soplón, Josep Grau-Valldosera and Julià Minguillón |
| Abstract: | Distance and online universities have usually more flexible academic requirements than brick-and-mortar ones, so students do not uniformly advance within the programme they enroll into as they are supposed to. Furthermore, due to their intrinsic nature, distance students need additional support for deciding which subjects they will take every semester. On the other hand, teachers have usually no idea about what other subjects are taking the students enrolled in their subjects. This paper proposes the use of chord diagrams for visualizing the relationships between pairs of subjects taken by students, with the aim of providing both university managers and students with a clear picture of possible bottlenecks, that is, combinations of subjects that might affect students’ performance. Chord diagrams can be used to analyze intra-semester data (subjects taken simultaneously) and inter-semester data (sequences of subjects taken by students) and provide a fast overview of what is happening within a given programme at subject level. Furthermore, it is possible to interact with chord diagrams in order to filter and obtain additional subject details if desired. |
Posters
| Paper Nr: | 18 |
| Title: | Versatile Scenario Guidance for Collaborative Virtual Environments |
| Authors: | Guillaume Claude, Valerie Gouranton and Bruno Arnaldi |
| Abstract: | Currently, the scenario of a virtual reality application depends greatly of the representation of the virtual environment and the goals of the application. Different needs arise from these elements such as the abstraction level of their events, the presence of multiple actors or their freedom of action. In this paper, we propose a scenario engine model that aims at being used in any virtual reality application where the scenario is a key feature. It differs from other models as it can be used without making any assumption on the simulation purpose or on the modelling of the Virtual Environment (events model, objects behaviour). |
| Paper Nr: | 23 |
| Title: | Science on a Sphere - Ways of Adding Interactivity into the Unique Projection System |
| Authors: | Jana Varnušková and Josef Kohout |
| Abstract: | This paper describes applied research provided in cooperation of the Faculty of Applied Sciences and the Techmania Science Centre. It presents the unique system Science on a Sphere, its features, control mechanisms and limitations. The special visualization system brings a new approach of geographical data presentation. On the other hand it offers just a minimal opportunity of user interaction. Interaction should enable better participation of science centre in the learning process. The paper shows the ways how the existing projection system Science on a Sphere has been extended for the interactive features. |
| Paper Nr: | 31 |
| Title: | Multimodal Interaction Techniques in Scientific Data Visualization - An Analytical Survey |
| Authors: | Jannik Fiedler, Stefan Rilling, Manfred Bogen and Jens Herder |
| Abstract: | The interpretation process of complex data sets makes the integration of effective interaction techniques crucial. Recent work in the field of human–computer interaction has shown that there is strong evidence that multimodal user interaction, i.e. the integration of various input modalities and interaction techniques into one comprehensive user interface, can improve human performance when interacting with complex data sets. However, it is still unclear which factors make these user interfaces superior to unimodal user interfaces. The contribution of this work is an analytical comparison of a multimodal and a unimodal user interface for a scientific visualization application. We show that multimodal user interaction with simultaneously integrated speech and gesture input improves user performance regarding efficiency and ease of use. |
| Paper Nr: | 31 |
| Title: | Multimodal Interaction Techniques in Scientific Data Visualization - An Analytical Survey |
| Authors: | Jannik Fiedler, Stefan Rilling, Manfred Bogen and Jens Herder |
| Abstract: | The interpretation process of complex data sets makes the integration of effective interaction techniques crucial. Recent work in the field of human–computer interaction has shown that there is strong evidence that multimodal user interaction, i.e. the integration of various input modalities and interaction techniques into one comprehensive user interface, can improve human performance when interacting with complex data sets. However, it is still unclear which factors make these user interfaces superior to unimodal user interfaces. The contribution of this work is an analytical comparison of a multimodal and a unimodal user interface for a scientific visualization application. We show that multimodal user interaction with simultaneously integrated speech and gesture input improves user performance regarding efficiency and ease of use. |
| Paper Nr: | 33 |
| Title: | Studying the User Experience with a Multimodal Pedestrian Navigation Assistant |
| Authors: | Gustavo Rovelo, Francisco Abad, M. C.- Juan and Emilio Camahort |
| Abstract: | The widespread usage of mobile devices together with their computational capabilities enables the implementation of novel interaction techniques to improve user performance in traditional mobile applications. Navigation assistance is an important area in the mobile domain, and probably Google Maps is the most popular example. This type of applications is highly demanding for user’s attention, especially in the visual channel. Tactile and auditory feedback have been studied as alternatives to visual feedback for navigation assistance to reduce this dependency. However, there is still room for improvement and more research is needed to understand, for example, how the three feedback modalities complement each other, especially with the appearance of new technology such as smart watches and new displays such as Google Glass. The goal of our work is to study how the users perceives multimodal feedback when their route is augmented with directional cues. Our results show that tactile guidance cues produced the worst user performance, both objectively and subjectively. Participants reported that vibration patterns were hard to decode. However, tactile feedback was an unobtrusive technique to inform participants when to look to the mobile screen or listen to the spoken directions. The results show that combining feedback modalities produces good user performance. |
| Paper Nr: | 61 |
| Title: | Virtual Agents and Multi-modality of Interaction in Multimedia Applications for Cultural Heritage - A Case Study |
| Authors: | João Neto, Claudia Ribeiro, João Pereira and Maria João Neto |
| Abstract: | Cultural Heritage encompasses a set of traditions and commodities inherited from our ancestors, and it is vital to convey and preserve them for the next generation. Cultural Multimedia applications and Serious Games form an important pedagogical and didactic medium, mainly for a young demography, which can learn while playing. In this paper is presented an innovative platform, named EI2VA (Engine for Immersive Interaction with Virtual Agents), in which a virtual character, endowed with facial, corporal and behavioural animation can be integrated in multimedia applications. These multimedia applications, derived from the Fala Comigo project, which set the example for a possible use of this technology, preserving the historical and cultural contents indispensable for the users, based on a multi-modality of evident interaction. The resulting multimedia applications were used in a case study conduct with three different user groups (experts and nonexperts) in different settings including classroom, museum and scientific conference. |
| Paper Nr: | 62 |
| Title: | Visualization of Music at Arm’s Length |
| Authors: | João Tiago Gomes, Maria Beatriz Carmo and Ana Paula Cláudio |
| Abstract: | This paper presents an interactive application to compose music. It aims to give anyone the possibility of creating music from various sounds that can be composed on top of each other to create music of increased complexity. The musical composition is accompanied by a 3D visualization that is intended to serve not only as a guide to the user’s composing process but also as a visualization of the music being created. A user study was conducted to assess the composition process, the interaction with a Leap Motion device and the correspondence between sound and visualization. |
| Paper Nr: | 65 |
| Title: | VR based Collaborative Errorless Learning System using Humanoid Avatar for People with Alzheimer’s Disease |
| Authors: | Takehiko Yamaguchi, Yuta Yamagami, Toshihiko Sato, Hibiki Fujino, Tetsuya Harada, Debora Alexandora Foloppe, Paul Richard and Philippe Allain |
| Abstract: | Everyday action impairment is one of the diagnostic criteria of Alzheimer’s disease and is associated with many serious consequences, including loss of functional autonomy and independence. It has been shown that the (re)learning of everyday activities is possible in Alzheimer’s disease by using errorless learning approaches. The purpose of this study is to propose a newly revised Virtual Kitchen system that allows training of everyday activities to integrate a new approach of errorless learning (EL) framework using collaborative learning with a virtual agent. In this paper, we describe a concept of the proposed framework, as well as explore user’s attention change to analyse eye tracking data during a training task in order to review the effectiveness of the proposed EL framework. |
| Paper Nr: | 71 |
| Title: | Investigating User Response to a Hybrid Sketch Based Interface for Creating 3D Virtual Models in an Immersive Environment |
| Authors: | Alexandra Bonnici, Johann Habakuk Israel, Anne Marie Muscat, Daniel Camilleri, Kenneth Camilleri and Uwe Rothenburg |
| Abstract: | Computer modelling of 2D drawings is becoming increasingly popular in modern design as can be witnessed in the shift of modern computer modelling applications from software requiring specialised training to ones targeted for the general consumer market. Despite this, traditional sketching is still prevalent in design, particularly so in the early design stages. Thus, research trends in computer-aided modelling focus on the the development of sketch based interfaces that are as natural as possible. In this paper, we present a hybrid sketch based interface which allows the user to make draw sketches using offline as well as online sketching modalities, displaying the 3D models in an immersive setup, thus linking the object interaction possible through immersive modelling to the flexibility allowed by paper-based sketching. The interface was evaluated in a user study which shows that such a hybrid system can be considered as having pragmatic and hedonic value. |
| Paper Nr: | 79 |
| Title: | Efficient Image Distribution on the Web - Instant Texturing for Collaborative Visualization of Virtual Environments |
| Authors: | Michael Englert, Yvonne Jung, Jonas Etzold, Marcel Klomann and Paul Grimm |
| Abstract: | In this paper, we present a browser-based Web 3D application that allows an instant distribution of image data even over mobile networks as well as textured rendering of large image collections on mobile devices with restricted processing power. Applications utilizing a lot of image data require an adaptive technology to build responsive user interfaces. This applies especially for the use in mobile networks. Furthermore the up- and download of the massive amount of image data should be transmitted in a progressive manner to get an instant feedback. While people are used to instant reaction of web applications and do not care about the amount of data that has to be transferred, the instantaneous display of imperfect content that gets continuously refined is state of the art for many application areas on the web. However, standard 2D image transmission technologies are usually inappropriate within a 3D context. In 2D, image size as well as resolution are often set during the authoring phase, whereas in 3D applications size and displayed resolution of textured 3D objects depend on the virtual camera. Our GPUII approach (GPU-based Image Interlacing) follows a client-server architecture, which allows an instant distribution of new data while also reducing the CPU load and network traffic. |
| Paper Nr: | 84 |
| Title: | Component-based Authoring Tool for Haptic Navigation |
| Authors: | Takehiko Yamaguchi, Kazuhiro Oshima, Yuto Hirano, Akiyo Makishima, Testsuya Harada and Paul Richard |
| Abstract: | Nowadays, providing a uniform development environment for haptic applications is considered as one of the critical issues in haptic technologies. Thus, to date, we have developed a component-based haptic authoring framework using a component capability extension mechanisms supported by Unity3D. Our aim is to develop a newly revised haptic component to extend our previous framework. The proposed component enables a user to design haptic interface such as haptic navigation, as well as to help simulate/investigate the effect of the haptic interaction. In this paper, we present a prototype system and its capabilities. |
| Paper Nr: | 85 |
| Title: | Design of Tangible Procedural Programming of Robots Based on Augmented Reality |
| Authors: | Satoshi Matsuzaki, Munehiro Takimoto and Yasushi Kambayashi |
| Abstract: | This paper presents a tool for children aged 5 to 11 to learn procedural programming through tiling tangible cards. In our tool, children are expected to tile square cards that respectively correspond to the unique operations of a robot while looking at them through a display, where the cards on the display are augmented by intuitive colorful images. Once each image is augmented, the image stays on the display even if the corresponding card is taken away. Also, the control flow from a card to another card is represented by a line image, which is created when one places a card close to another card. In our tool, editing operations such as undo, erase, and setting arguments can be also performed through movements of a special card. For feasibility study, we have had one hundred students of primary schools use our tool. As a result, they learned programming more quickly than programming in an existing tool where programs are composed through tiling icons. |
| Paper Nr: | 87 |
| Title: | Human-human Collaboration Formalism for Groupware Tailorability in Collaborative Augmented Environments |
| Authors: | Samir Benbelkacem, Nadia Zenati-Henda, Hayet Belghit, Samir Otmane and Abdelkader Bellarbi |
| Abstract: | In this paper, human-human collaboration formalism has been proposed to support groupware tailorability for Collaborative Augmented Environments (CAE). Our work is based on the 3C functional model proposed by Ellis. This model decomposes the collaboration into communication, coordination and production. This decomposition has been adapted to design tailorable groupware for CAE. A new concept called “distribution” has been introduced to consider the properties of collaborative and distributed 3D environment. A new formalism integrating this concept is proposed in order to adapt a groupware system to the real need of users evolving in 3D shared scene. Multi-agent technology is, therefore, used to determine the collaboration protocol between humans, through machines, over the network for implementing the desired tailorability. |
| Paper Nr: | 94 |
| Title: | On Visualizing Movements and Activities of Healthy Seniors - An Overview |
| Authors: | Shahram Payandeh |
| Abstract: | Increased life expectancy and motivational support for the pursuit of independent living for active seniors have been introducing a number of challenges for the families and care monitoring personnel. In general, this class of aging seniors are healthy enough that they can afford to continue to have the independent living life styles but also are old enough that one still needs to have some levels of monitoring of their movements and activities in their private dwellings. These motions and activities can be monitored through a network of connected sensors at each individual’s dwelling where they can be networked to form a monitoring cluster. The objective is then to be able to present and visualize such movements and activities information to the monitoring personnel. This paper reviews various sensing modalities which can be used in monitoring movements and activities of seniors and presents an overview of visualization techniques which have been utilized in various similar applications. In addition the paper highlights a conceptual framework which can be used to visualize movements and activities in a cluster of such sensor network. |
| Paper Nr: | 96 |
| Title: | Generating Non-linear Narrative for Serious Games with Scenario Templates |
| Authors: | Koen Samyn, Gaetan Deglorie, Peter Lambert, Rik Van de Walle and Sofie Van Hoecke |
| Abstract: | Complex social interactions between NPC’s and players in a serious game remains a challenge. Standard game engines are focused on a game world with a fixed set of rules and linear gameplay. The problem is compounded by the unfamiliarity of many researchers with the basic structure and technicalities of a serious game. In this paper we propose a method to use linear scenario elements as templates for the generation of a non-linear narrative. We implement this method by creating an extra layer on top of the existing ATTAC-L modeling language which is a tool for developing virtual interactive scenarios. Users are thus presented with a language that offers limited flow control and simplifies the authoring process for the creation of scenario elements. Our method uses these existing scenario elements together with metadata, and fills in the templated elements with the contextual information of the current game state. By separating scenario concerns from non-linear narrative concerns, we hope to make it easier to develop interesting non-linear serious games that still conform to the requirements of evidence-based serious game research. |