CosmoScout VR: A Modular 3D Solar System Based on SPICE

We present CosmoScout VR - a modular 3D Solar System for interactive exploration and presentation of large space mission datasets. This paper describes the overall architecture as well as several core components of the frame-work. To foster the application in various scientific domains, CosmoScout VR employs a plugin-based architecture. This not only reduces development times but also allows scientists to create their own data visualization plugins without having to modify the core source code of CosmoScout VR. One of the most important plugins - level-of-detail terrain rendering - is described in greater detail in this paper. Another key feature of CosmoScout VR is the scene graph which is tightly coupled with NASA's SPICE library to allow for high-precision positioning of celestial objects, such as planets, moons, and spacecrafts. SPICE is also used for the seamless navigation throughout the Solar System in which the user automatically follows the closest body. During navigation, the virtual scene is scaled in such a way, that the closest celestial body is always within arm's reach. This allows for simultaneous exploration of multiple datasets in their spatial context at diverse scales. However, the navigation uses all six degrees of freedom which can induce motion sickness. In this paper, we present some counter measures as well as evaluate their effectiveness in a user study. CosmoScout VR is open source, cross-platform, and while it can run on conventional desktop PCs, it also supports stereoscopic multi-screen systems, such as display walls, DOMEs or CAVEs

Real-Time Rendering of Eclipses without Incorporation of Atmospheric Effects

In this paper, we present a novel approach for real-time rendering of soft eclipse shadows cast by spherical, atmosphereless bodies. While this problem may seem simple at first, it is complicated by several factors. First, the extreme scale differences and huge mutual distances of the involved celestial bodies cause rendering artifacts in practice. Second, the surface of the Sun does not emit light evenly in all directions (an effect which is known as limb darkening). This makes it impossible to model the Sun as a uniform spherical light source. Finally, our intended applications include real-time rendering of solar eclipses in virtual reality, which require very high frame rates. As a solution to these problems, we precompute the amount of shadowing into an eclipse shadow map, which is parametrized so that it is independent of the position and size of the occluder. Hence, a single shadow map can be used for all spherical occluders in the Solar System. We assess the errors introduced by various simplifications and compare multiple approaches in terms of performance and precision. Last but not least, we compare our approaches to the state-of-the-art and to reference images. The implementation has been published under the MIT license

Comparison of Depth Buffer Techniques for Large and Detailed 3D Scenes

Large scale 3D scenes in applications like space simulations are often subject to depth buffer related issues and visual artefacts like Z-fighting and spatial jittering. These issues are primarily a result of indistinguishable depth buffer values. To mitigate these issues, many techniques have been developed over time to better distribute depth values over the clipping range. These techniques range from simple adjustments of the projection matrix to complex solutions like multistage rendering with layered depth buffers. This work presents, compares and evaluates commonly used approaches found in iterature and real world applications. An experiment is set up to compare the presented depth buffer techniques using the metric of minimum triangle separation (MTS). The gathered results are presented and evaluated, to give a good overview on which techniques are well suited for the use in applications with large scale 3D scenes

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

STRIELAD - A Scalable Toolkit for Real-time Interactive Exploration of Large Atmospheric Datasets

Technological advances in high performance computing and maturing physical models allow scientists to simulate weather and climate evolutions with an increasing accuracy. While this improved accuracy allows us to explore complex dynamical interactions within such physical systems, inconceivable a few years ago, it also results in grand challenges regarding the data visualization and analytics process. We present STRIELAD, a scalable weather analytics toolkit, which allows for interactive exploration and real-time visualization of such large scale datasets. It combines parallel and distributed feature extraction using high-performance computing resources with smart level-of-detail rendering methods to assure interactivity during the complete analysis process

Real-time Interactive Exploration of Large Atmospheric Datasets in Virtual Reality

While technological advances in high performance computing allow for an ever-increasing accuracy in climate and weather simulations, they also lead to grand challenges regarding the data visualization and analytics process. We present a visualization framework, which allows for interactive exploration and real-time visualization of such large scale datasets in virtual reality. It combines parallel and distributed feature extraction using high-performance computing resources with octree-based level-of-detail rendering methods to assure high frame rates during the complete analysis process. When parameters such as an iso-value or the current time-step are modified, the visualization is updated progressively in a view-dependent manner. In addition, the data is shown in relation to the geographical, planetary and celestial context: the data is shown as part of our solar system. Planets are rendered with a sophisticated level-of-detail system based on the HEALPix tessellation of spheres. HEALPix tiles have equal areas and do not suffer from singularities at poles which are a common issue with other tessellations. Geographical datasets (e.g. Satellite images, digital elevation data or vector maps) are loaded from Web-Map-Services (WMS). Example datasets for Earth include, but are not limited to, Sentinel images, Open Street Map, TanDEM-X or SRTM30. NASA's SPICE library is used to compute the position of sun, planets, moons and stars

Immersive and Interactive 3D Visualization of Large-Scale Geo-Scientific Data

In this paper, we present a software architecture and framework developed over the past decade to enable scalable and highly interactive visualizations for large datasets and display sizes. The framework integrates distributed data processing, data streaming, and dynamic scheduling to allow for view-dependent feature extraction and progressive data streaming. Additionally, the framework has been designed to support visualizations from local desktop workstations to large multi-display virtual environments

Programmable Logic Gates Based On Tunable Multistable Mechanisms

Binary logic operations are the building blocks of computing machines. In this paper, we present a new programmable binary logic gate based on programmable multistable mechanisms (PMM), which are multistable structures whose stability behavior depends on modifiable boundary conditions as defined and analyzed in our previous work. The logical state of a PMM is defined by its stability and logical operations are implemented by modifying the stability behavior of the mechanism.Our programmable logic device has two qualitatively different sets of inputs. The first set determines the logic function to be computed. The second set represents the logical inputs. The output is a single logical value, "true" if the mechanism changes state and "false" otherwise. In this way, we are able to mechanically implement a set of binary logical operations.This implementation is validated using an analytical model characterizing the qualitative stability behavior of the mechanism. This was further verified using finite element analysis and experimental demonstration