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The visual analysis of surface cracks plays an essential role in tunnel maintenance when assessing the condition of a tunnel. To identify patterns of cracks, which endanger the structural integrity of its concrete surface, analysts need an integrated solution for visual analysis of geometric and multivariate data to decide if issuing a repair project is necessary. The primary contribution of this work is a design study, supporting tunnel crack analysis by tightly integrating geometric and attribute views to allow users a holistic visual analysis of geometric representations and multivariate attributes. Our secondary contribution is Visual Analytics and Rendering, a methodological approach which addresses challenges and recurring design questions in integrated systems. We evaluated the tunnel crack analysis solution in informal feedback sessions with experts from tunnel maintenance and surveying. We substantiated the derived methodology by providing guidelines and linking it to examples from the literature.

Panoramic camera systems on robots exploring the surface of Mars are used to collect images of terrain and rock outcrops which they encounter along their traverse. Image mosaics from these cameras are essential in mapping the surface geology and selecting locations for analysis by other instruments on the rover's payload. 2‐D images do not truly portray the depth of field of features within an image, nor their 3‐D geometry. This paper describes a new 3‐D visualization software tool for geological analysis of Martian rover‐derived Digital Outcrop Models created using photogrammetric processing of stereo‐images using the Planetary Robotics Vision Processing tool developed for 3‐D vision processing of ExoMars PanCam and Mars 2020 Mastcam‐Z data. Digital Outcrop Models are rendered in real time in the Planetary Robotics 3‐D Viewer PRo3D, allowing scientists to roam outcrops as in a terrestrial field campaign. Digitization of point, line, and polyline features is used for measuring the physical dimensions of geological features and communicating interpretations. Dip and strike of bedding and fractures is measured by digitizing a polyline along the contact or fracture trace, through which a best fit plane is plotted. The attitude of this plane is calculated in the software. Here we apply these tools to analysis of sedimentary rock outcrops and quantification of the geometry of fracture systems encountered by the science teams of NASA's Mars Exploration Rover Opportunity and Mars Science Laboratory rover Curiosity. We show the benefits PRo3D allows for visualization and collection of geological interpretations and analyses from rover‐derived stereo‐images., Earth and Space Science, 5 (7), ISSN:2333-5084

3D visibility analysis plays a key role in urban planning for assessing the visual impact of proposed buildings on the cityscape. A call for proposals typically yields around 30 candidate buildings that need to be evaluated with respect to selected viewpoints. Current visibility analysis methods are very time-consuming and limited to a small number of viewpoints. Further, analysts neither have measures to evaluate candidates quantitatively, nor to compare them efficiently. The primary contribution of this work is the design study of Vis-A-Ware, a visualization system to qualitatively and quantitatively evaluate, rank, and compare visibility data of candidate buildings with respect to a large number of viewpoints. Vis-A-Ware features a 3D spatial view of an urban scene and non-spatial views of data derived from visibility evaluations, which are tightly integrated by linked interaction. To enable a quantitative evaluation we developed four metrics in accordance with experts from urban planning. We illustrate the applicability of Vis-A-Ware on the basis of a use case scenario and present results from informal feedback sessions with domain experts from urban planning and development. This feedback suggests that Vis-A-Ware is a valuable tool for visibility analysis allowing analysts to answer complex questions more efficiently and objectively.

This paper focuses on the distributed architecture of the collaborative threedimensional user interface management system, Studierstube. The system allows multiple users to experience a shared 3D workspace populated by multiple applications using see-through head-mounted displays or other presentation media such as projection systems. Building large, ubiquitous, or mobile workspaces requires distribution of applications over several hosts in varying and dynamic configurations. The system design is based on a distributed shared scene graph that alleviates the application programmer from explicitly considering distribution and that avoids a separation of graphical and application data. The idea of unifying all system data in the scene graph is taken to its logical consequence by implementing application instances as nodes in the scene graph. Through the distributed shared scene graph mechanism, consistency of scene graph replicas and the contained application nodes is assured. Dynamic configuration management is based on application migration between participating hosts and a spatial model of locales allowing dynamic workgroup management. We describe a number of experimental workspaces that demonstrate the use of these configuration management techniques.

We present a system to evaluate and improve visual guidance systems and signage for pedestrians inside large buildings. Given a 3D model of an actual building we perform agent-based simulations mimicking the decision making process and navigation patterns of pedestrians trying to find their way to predefined locations. Our main contribution is to enable agents to base their decisions on realistic threedimensional visibility and occlusion cues computed from the actual building geometry with added semantic annotations (e.g. meaning of signs, or purpose of inventory), as well as an interactive visualization of simulated movement trajectories and accompanying visibility data tied to the underlying 3D model. This enables users of the system to quickly pinpoint and solve problems within the simulation by watching, exploring and understanding emergent behavior inside the building. This insight gained from introspection can in turn inform planning and thus improve the effectiveness of guidance systems.

The behavior of a large number of persons in big buildings is pretty difficult to predict. Long time observations have to be made and many things have to be tested in the real environment, for example how to route people around locked escalators, how to place vending or ticket machines, or how to place various kinds of advertisements. A lot of experience is needed to make the right decisions and mistakes and omissions can easily happen.Models of buildings and simulations can improve the analysis of such environments where many people move about. A good visualization of human behavior in these models can be a great help in planning and improve the quality of necessary changes. It is also possible to analyze the focus of persons who are wandering around in the building, before performing actual changes and thus judge the impact of various alternatives.A major problem is that for most buildings no adequate 3D models to perform such visualizations exist. Current building models need modeling experts for manipulation, and current simulation software needs simulation experts for analyzing movement of people within a building.Ideally, simulated movement of people should be presented in a recognizable 3D model in such a way that it can be easily identified and interpreted without further explanation. It should also be possible to manipulate the building and automatically trigger the changed simulation in the background, without being an expert. This should make it possible to explore alternative planning scenarios and improve the applicability of an envisioned planning tool.This paper presents a way to create an indoor person behavior visualization shown in its application to railway stations. The models are based on a combination of image based reconstruction and existing models of public buildings. The possibility to easily change the environment on the fly creates many possibilities to analyze alternative places for advertisement, vending and ticket machines. Therefore experiments on the real environment can be avoided to save a lot of time and money and increase customer satisfaction.

This paper focuses on the distributed architecture of the collaborative augmented reality system Studierstube. The system allows multiple users to experience a shared 3D workspace populated by multiple applications using see-through head mounted displays or other presentation media such as projection systems. The system design is based on a distributed shared scene graph that alleviates the application programmer from explicitly considering distribution, and avoids a separation of graphical and application data. The idea of unifying all system data in the scene graph is taken to its logical consequence by implementing application instances as nodes in the scene graph. Through the distributed shared scene graph mechanism, consistency of scene graph replicas and the contained application nodes is assured. Multi-user 3D widgets allow concurrent interaction with minimal coordination effort from the application. Special interest is paid to migration of application nodes from host to host allowing dynamic workgroup management, such as load balancing, late joining and early exit of hosts, and some firms of ubiquitous computing.

Internet-based virtual environments (VEs) let users explore multiple virtual worlds with many different geometric models, which are downloaded rather than pre-distributed. To avoid long download times, we have developed a method that optimally utilizes network bandwidth by downloading only the exact portion of geometry that is necessary for rendering. The solution is based on progressive geometry data structures (smooth levels of detail) and on selective downloading.

Studierstube is an experimental user interface system which uses collaborative augmented reality to incorporate true 3D interaction into a productivity environment. This concept is extended to bridge multiple user interface dimensions by including multiple users, multiple host platforms, multiple display types, multiple concurrent applications and a multi-context (i.e. 3D document) interface into a heterogeneous distributed environment. With this architecture, we can explore the user interface design space between pure augmented reality and the popular ubiquitous computing paradigm. We report on our design philosophy, which is centered around the notion of contexts and locales, as well as the underlying software and hardware architecture. Contexts encapsulate a live application together with 3D (visual) and other data, while locales are used to organize geometric reference systems. By separating geometric relationships (locales) from semantic relationships (contexts), we achieve a great amount of flexibility in the configuration of displays. To illustrate our claims, we present several applications, including a cinematographic design tool which showcases many features of our system.

Distributed Open Inventor is an extension to the popular Open Inventor toolkit for interactive 3D graphics. The toolkit is extended with the concept of a distributed shared scene graph, similar to distributed shared memory. From the application programmer's perspective, multiple workstations share a common scene graph. The proposed system introduces a convenient mechanism for writing distributed graphical applications based on a popular tool in an almost transparent manner. Local variations in the scene graph allow for a wide range of possible applications, and local low latency interaction mechanisms called input streams enable high performance while saving the programmer from network peculiarities.

International audience; The continuously increasing complexity of computer animationsmakes it necessary to rely on the knowledge of various experts to cover the different areas of computer graphics and animation. This fact, which can be noted in many areas of scientific working, leads to increasing effort being put into research concerning cooperative working over the internet. However, it still requires substantialeffort and time to combine different animation techniques in a common virtual environment. When trying to perform collaborative animation over a network, we often face the problem of having to combine animation systems and applications based on different software and hardware and using incompatible data structures. We present an approach, based on a client-server architecture and employing a VRML-based language as common interchange format, that allows inhomogeneous systems to be easily incorporated into a collaborative animation. The applications can be freed from employing plug-ins or libraries to link into a common animation platform; they keep a local copy of the global scene and only need the ability to export the internal data representation into the so called ”PaVRML” language, the language we use use to exchange data and synchronize the clients. This approach does not only allow a number of practitioners to share their know-how within a common animation without requiring the huge amount of work necessary to port their application to a common platform. It also makes it often possible in the first place to combine the capabilities of different animation systems into a single complex animation. Additionally, we investigate solutions to optimize the network load for real-time applications. In this paper we present preliminary results and discuss the future developments of this ongoing work.