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Item Interactive Projective Texturing for Non-Photorealistic Shading of Technical 3D Models(The Eurographics Association, 2013) Lux, Roland; Trapp, Matthias; Semmo, Amir; Döllner, JĂĽrgen; Silvester Czanner and Wen TangThis paper presents a novel interactive rendering technique for creating and editing shadings for man-made objects in technical 3D visualizations. In contrast to shading approaches that use intensities computed based on surface normals (e.g., Phong, Gooch, Toon shading), the presented approach uses one-dimensional gradient textures, which can be parametrized and interactively manipulated based on per-object bounding volume approximations. The fully hardware-accelerated rendering technique is based on projective texture mapping and customizable intensity transfer functions. A provided performance evaluation shows comparable results to traditional normal-based shading approaches. The work also introduce simple direct-manipulation metaphors that enables interactive user control of the gradient texture alignment and intensity transfer functions.Item Sketching for Real-time Control of Crowd Simulations(The Eurographics Association, 2017) Gonzalez, Luis Rene Montana; Maddock, Steve; Tao Ruan Wan and Franck VidalCrowd simulations are used in various fields such as entertainment, training systems and city planning. However, controlling the behaviour of the pedestrians typically involves tuning of the system parameters through trial and error, a time-consuming process relying on knowledge of a potentially complex parameter set. This paper presents an interactive graphical approach to control the simulation by sketching in the simulation environment. The user is able to sketch obstacles to block pedestrians and lines to force pedestrians to follow a specific path, as well as define spawn and exit locations for pedestrians. The obstacles and lines modify the underlying navigation representation and pedestrian trajectories are recalculated in real time. The FLAMEGPU framework is used for the simulation and the game engine Unreal is used for visualisation. We demonstrate the effectiveness of the approach using a range of scenarios, producing interactive editing and frame rates for tens of thousands of pedestrians. A comparison with the commercial software MassMotion is also given.Item Natural Phenomena as Metaphors for Visualization of Trend Data in Interactive Software Maps(The Eurographics Association, 2015) WĂĽrfel, Hannes; Trapp, Matthias; Limberger, Daniel; Döllner, JĂĽrgen; Rita Borgo and Cagatay TurkaySoftware maps are a commonly used tool for code quality monitoring in software-development projects and decision making processes. While providing an important visualization technique for the hierarchical system structure of a single software revision, they lack capabilities with respect to the visualization of changes over multiple revisions. This paper presents a novel technique for visualizing the evolution of the software system structure based on software metric trends. These trend maps extend software maps by using real-time rendering techniques for natural phenomena yielding additional visual variables that can be effectively used for the communication of changes. Therefore, trend data is automatically computed by hierarchically aggregating software metrics. We demonstrate and discuss the presented technique using two real world data sets of complex software systems.Item GPU Simulation of Finite Element Facial Soft-Tissue Models(The Eurographics Association, 2013) Warburton, Mark; Maddock, Steve; Silvester Czanner and Wen TangPhysically-based animation techniques enable more realistic and accurate animation to be created. We present a GPU-based finite element (FE) simulation and interactive visualisation system for efficiently producing realisticlooking animations of facial movement, including expressive wrinkles. It is optimised for simulating multi-layered voxel-based models using the total Lagrangian explicit dynamic (TLED) FE method. The flexibility of our system enables detailed animations of gross and fine-scale soft-tissue movement to be easily produced with different muscle structures and material parameters. While we focus on the forehead, the system can be used to animate any multi-material soft body.Item Measuring Realism in Hair Rendering(The Eurographics Association, 2013) Ramesh, Girish; Turner, Martin J.; Silvester Czanner and Wen TangVisualisation of hair is an extremely complex problem within the field of Computer Graphics. Over the last 10 years, huge strides have been made in the area of physically-based hair rendering, giving rise to many applications in various fields other than the graphics industry. Given the number of models for hair rendering, there is no well defined evaluation process to measure the realism in the hair models in use today. For this work-in-progress paper, we propose an evaluation process not only to evaluate the realism in hair rendering models, but also examine the various effects that contribute to its realistic perception. This builds an index of realism based on experiments with computer generated models, and then proposes comparing the results with values obtained from computational tomography, optical imaging and goniophotometer readings.Item Path Tracing on Massively Parallel Neuromorphic Hardware(The Eurographics Association, 2012) Richmond, Paul; Allerton, David J.; Hamish Carr and Silvester CzannerRay tracing on parallel hardware has recently benefit from significant advances in the graphics hardware and associated software tools. Despite this, the SIMD nature of graphics card architectures is only able to perform well on groups of coherent rays which exhibit little in the way of divergence. This paper presents SpiNNaker, a massively parallel system based on low power ARM cores, as an architecture suitable for ray tracing applications. The asynchronous design allows us to demonstrate a linear performance increase with respect to the number of cores. The performance perWatt ratio achieved within the fixed point path tracing example presented is far greater than that of a multi-core CPU and similar to that of a GPU under optimal conditions.Item Light Clustering for Dynamic Image Based Lighting(The Eurographics Association, 2012) Staton, Sam; Debattista, Kurt; Bashford-Rogers, Thomas; Chalmers, Alan; Hamish Carr and Silvester CzannerHigh Dynamic Range (HDR) imagery has made it possible to relight virtual objects accurately with the captured lighting. This technique, called Image Based Lighting (IBL), is a commonly used to render scenes using real-world illumination. IBL has mostly been limited to static scenes due to limitations of HDR capture. However, recently there has been progress on developing devices which can capture HDR video sequences. These can be also be used to light virtual environments dynamically. If existing IBL algorithms are applied to this dynamic problem, temporal artifacts viewed as flickering can often arise due to samples being selected from different parts of the environment in consecutive frames. In this paper we present a method for efficiently rendering virtual scenarios with such captured sequences based on spatial and temporal clustering. Our proposed Dynamic IBL (DIBL) method improves temporal quality by suppressing flickering, and we demonstrate the application to fast previews of scenes lit by video environment maps.Item PED: Pedestrian Environment Designer(The Eurographics Association, 2016) McIlveen, James; Maddock, Steve; Heywood, Peter; Richmond, Paul; Cagatay Turkay and Tao Ruan WanPedestrian simulations have many uses, from pedestrian planning for architecture design through to games and entertainment. However, it is still challenging to efficiently author such simulations, especially for non-technical users. Direct pedestrian control is usually laborious, and, while indirect, environment-level control is often faster, it currently lacks the necessary tools to create complex environments easily and without extensive prior technical knowledge. This paper describes an indirect, environment-level control system in which pedestrians' behaviour can be specified efficiently and then interactively tuned. With the Pedestrian Environment Designer (PED) interface, authors can define environments using tools similar to those found in raster graphics editing software such as PhotoshopTM. Users paint on two-dimensional bitmap layers to control the behaviour of pedestrians in a three-dimensional simulation. The layers are then compiled to produce a live, agent-based pedestrian simulation using the FLAME GPU framework. Entrances and exits can be inserted, collision boundaries defined, and areas of attraction and avoidance added. The system also offers dynamic simulation updates at runtime giving immediate author feedback and enabling authors to simulate scenarios with dynamic elements such as barriers, or dynamic circumstances such as temporary areas of avoidance. As a result, authors are able to create complex crowd simulations more effectively and with minimal training.Item A Cost Effective, Accurate Virtual Camera System for Games, Media Production and Interactive Visualisation Using Game Motion Controllers(The Eurographics Association, 2013) Bett, Matthew; Michno, Erin; McAlpine, Keneth B.; Silvester Czanner and Wen TangVirtual cameras and virtual production techniques are an indispensable tool in blockbuster filmmaking but due to their integration into commercial motion-capture solutions, they are currently out-of-reach to low-budget and amateur users. We examine the potential of a low budget high-accuracy solution to create a simple motion capture system using controller hardware designed for video games. With this as a basis, a functional virtual camera system was developed which has proven usable and robust for commercial testing.Item gVirtualXRay: Virtual X-Ray Imaging Library on GPU(The Eurographics Association, 2017) Sujar, Aaron; Meuleman, Andreas; Villard, Pierre-Frederic; GarcĂa, Marcos; Vidal, Franck; Tao Ruan Wan and Franck VidalWe present an Open-source library called gVirtualXRay to simulate realistic X-ray images in realtime. It implements the attenuation law (also called Beer-Lambert) on GPU. It takes into account the polychromatism of the beam spectra as well as the finite size of X-ray tubes. The library is written in C++ using modern OpenGL. It is fully portable and works on most common desktop/laptop computers. It has been tested on MS Windows, Linux, and Mac OS X. It supports a wide range of windowing solutions, such as FLTK, GLUT, GLFW3, Qt4, and Qt5. The library also offers realistic visual rendering of anatomical structures, including bones, liver, diaphragm and lungs. The accuracy of the X-ray images produced by gVirtualXRay's implementation has been validated using Geant4, a well established state-of-the-art Monte Carlo simulation toolkit developed by CERN. gVirtualXRay can be used in a wide range of applications where fast and accurate X-ray simulations from polygon meshes are needed, e.g. medical simulators for training purposes, simulation of tomography data acquisition with patient motion to include artefacts in reconstructed CT images, and deformable registration. Our application example package includes real-time respiration and X-ray simulation, CT acquisition and reconstruction, and iso-surfacing of implicit functions using Marching Cubes.