As Virtual Reality (VR) is becoming a readily available tool in an increasing number of fields, we see also an increasing number of non-technical users entering virtual environments (VEs). One pose manipulation technique that has the potential to be both fast and intuitive to use, is the Hand-centered Object Manipulation Extending Ray-casting (HOMER), presented first by Bowman and Hodges [1]. In this paper we take a look at how a naive implementation of HO-MER can lead to unintuitive interaction and present mathematics for avoiding this problem, by using a rotational offset of the grab vector instead of a static offset vector. Subsequently we compare the naive and rotation-based versions with respect to task completion time and number of re-grabs, and measure their respective System Usability Scale (SUS) score and Raw NASA Task Load Index (RTLX)

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Rapid nanoscientific development in a myriad of applied fields compels educational structures to develop curricular nanoknowledge for a future citizenry capable of contributing skills to a nano-workforce and in acquiring a nano-literacy. This study investigated ten Swedish upper-secondary students' interactions with a virtual reality nanoworld and sought to illuminate: 1) how students link to and support their understanding of prior science knowledge, 2) students' attitudes towards the benefits and risks of nanotechnology, and 3) the usability of the system. Analyzed videotaped and written data elicited cognitive mechanisms underlying interaction with the virtual reality environment for promoting understanding, the influence of the interactive experience on students' attitudes to nanophenomena, and system features that could be applied in real science classrooms.

Different aspects of bone surgery simulation has been a popular topic in haptics research field. This demonstration paper has two major results: a Free and Open Source Software (FOSS) implementation of a well known algorithm for tool-bone interaction force estimation, and an evaluation conducted as part of a suggested User-centered design approach for creation of a surgery simulator targeting Oral Surgery in particular.

Public understanding of contemporary scientific issues is critical for the future of society. Public spaces, such as science centers, can impact the communication of science by providing active knowledge-building experiences of scientific phenomena. In contributing to this vision, we have previously developed an interactive visualization as part of a public exhibition about nano. We reflect on how the immersive design and features of the exhibit contribute as a tool for science communication in light of the emerging paradigm of exploranation, and offer some forward-looking perspectives about what this notion has to offer the domain.

Recent educational research has suggested that immersive multisensory virtual environments offer learners unique and exciting knowledge-building opportunities for the construction of scientific knowledge. This paper delivers a case-based study of students’ immersive interaction with electric fields around molecules in a multisensory visuohaptic virtual environment. The virtual architecture presented here also has conceptual connections to the flourishing quest in contemporary literature for the pressing need to communicate nanoscientific ideas to learners. Five upper secondary school students’ prior conceptual understanding of electric fields and their application of this knowledge to molecular contexts, were probed prior to exposure to the virtual model. Subsequently, four students interacted with the visuohaptic model while performing think-aloud tasks. An inductive and heuristic treatment of videotaped verbal and behavioural data revealed distinct interrelationships between students’ interactive strategies implemented when executing tasks in the virtual system and the nature of their conceptual knowledge deployed. The obtained qualitative case study evidence could serve as an empirical basis for informing the rendering and communication of overarching nanoscale ideas. At the time of composing this paper for publication in the current journal, the research findings of this study have been put into motion in informing a broader project goal of developing educational virtual environments for depicting nanophenomena.

Visualizing molecular properties is often crucial for constructing conceptual understanding in chemistry. However, research has revealed numerous challenges surrounding students' meaningful interpretation of the relationship between the geometry and electrostatic properties of molecules. This study explored students' (n = 18) use of three visual representations of electrostatic potential to interpret whether molecules are polar or nonpolar. The representations consisted of red and blue 'lobes' (termed RB) indicating regions of negative and positive potential, a color gradient mapping electrostatic potential on a molecular surface (MAP), and a rendering of the interface between regions of positive and negative potential (ISO). Data on students' accuracy, time-on-task, and evaluation related to the three visual modes were collected via a Web-based questionnaire. ANOVA indicated that students were significantly more accurate in interpreting ISO representations, although almost half evaluated this mode as the most difficult to use. Furthermore, students took significantly longer to interpret complex molecules than simple molecules using ISO and RB. The results indicate that there may be possible pedagogical benefits in using unconventional visual representations that reduce visual complexity by making molecular relationships explicit. Hence, this has implications for future work on the role of cognitively mapping between different instructional visualizations in the development of fundamental chemical concepts.

This study aimed to investigate students’ assignment of chemical polarity using three visual modes representing electrostatic potential. The modes consisted of coloured lobes that indicate regions of negative (red) and positive (blue) potential, a colour gradient that maps the potential on the molecular surface and a novel representation that uses green surface(s) to show the interface between regions of positive and negative potential. Students’ ability to assign polarity using the three visual modes was evaluated using a web-questionnaire. Mean scores indicated that students were able to successfully assign polarity to molecules using all the modes. However, students were less successful in identifying polar molecules in comparison with non-polar molecules using the map mode. A possible explanation for the lower scores for this mode is that the representational power of the map as a polarity assignment tool could be compromised by the visual complexity of the colour gradient, especially when a molecule is polar. The green surface representation was found to be a sensitive visual tool for assigning polarity to molecules, an encouraging finding since students were exposed to this visual mode for the first time. Given the possible perceptual constraints associated with the map mode, the results of this study might serve as a basis for uncovering the best conditions for pursuing a multiple representations approach to teaching chemical polarity.

Public understanding of contemporary scientific issues is critical for the future of society. Public spaces, such as science centers, can impact the communication of science by providing active knowledge-building experiences of scientific phenomena. In contributing to this vision, we have previously developed an interactive visualization as part of a public exhibition about nano. We reflect on how the immersive design and features of the exhibit contribute as a tool for science communication in light of the emerging paradigm of exploranation, and offer some forward-looking perspectives about what this notion has to offer the domain.

In this article, we present a digital platform for unmanned traffic management, UTM City, for research on visualization, simulation, and management of autonomous urban vehicle traffic. Such vehicles orient themselves automatically and provide services ranging from transport to remote presence and surveillance, and new regulations and standards for authorization and monitoring are currently being developed to accommodate for such services. Our system has been developed in close collaboration with domain experts that have contributed with scenarios and participated in numerous workshops to explore the use of visualization in airborne drone traffic monitoring, management, and development of the air space. We share here our experiences with this system and explore the need for visualization in future scenarios to ensure safe, free, and efficient air spaces.

With the widespread use of deformation simulations in medical applications, the realism of the force feedback has become an important issue. In order to reach real-time performance with sufficient realism the approach of adaptivity, solution of different parts of the system with different resolutions and refresh rates, has been commonly deployed. The change in accuracy resulting from the use of adaptivity, however, has been been paid scant attention in the deformation simulation field. Presentation of error metrics is rare, while more focus is given to the real-time stability. We propose an abstract pipeline to perform error analysis for different types of deformation techniques which can consider different simulation parameters. A case study is also performed using the pipeline, and the various uses of the error estimation are discussed.

Virtual coupling, a spring-damper system between the haptic probe and its virtual representation, the proxy, is one of the most common approaches for haptic rendering. We have extended the virtual coupling by updating the spring stiffness, sometimes used to simulate compliance of a material, depending on the direction between the proxy and the probe. This anisotropic variation of the stiffness is used in exploring inhomogeneities beneath the surface allowing detection of rigid structures even when they are obscured by another structure beneath the surface. In addition, we also compensate for the energy variation of the spring to maintain passivity and increase realism. User studies were performed to survey the success rate in the detection of obscured rigid bodies beneath the surface with the modified virtual coupling algorithm and the improvement of shape perception for sub-surface objects with the additional energy compensation term providing gradient information. We also discuss potential benefits of the proposed methods as basic extensions to well-known haptic rendering algorithms which are both simpler and yield improved performance over traditional deformation simulationtechniques.

Achieving sufficient realism in deformation simulations requires consideration  of complex physical properties. The computational burden of modelling these properties requires the use of low resolution meshes to attain real time interactive performance. Medical data such as MR and CT, on the other hand, have much higher resolutions than can be practically used in deformation simulations. This results in significant amount of information loss, degenerating the ability to perceive variations in the data, especially inhomogeneities. In this paper, we address this issue by employing surfacerendering algorithms which can provide high resolution information from beneath the surface. An experiment was performed in a scenario simulating inhomogeneities of bone structure under the skin. Results have shown significant improvement for detecting inhomogeneities within deformable data while palpating the surface.

Understanding and explaining perception of touch is a non-trivial task. Even seemingly trivial differences in exploration may potentially have a significant impact on perception and levels of discrimination. In this study, we explore different aspects of contact related to stiffness perception and their effects on the just noticeable difference (JND) of stiffness are surveyed. An experiment has been performed on non-deformable, compliant objects in a virtual environment with three different types of contact: Discontinuous pressure, continuous pressure and continuous lateral motion. The result shows a significantly better discrimination performance in the case of continuous pressure (a special case of nonlinearity), which can be explained by the concept of haptic memory. Moreover, it is found that the perception is worse for the changes that occur along the lateral axis than the normal axis.

In order to simulate both physically and visually realistic soft tissue deformations, the Finite Element Method (FEM) is the mostpopular choice in the literature. However it is non-trivial to modelcomplex behaviour of soft tissue with sufficient refresh rates, especiallyfor haptic force feedback which requires an update rate ofthe order of 1 kHz. In this study the use of asynchronous regions isproposed to speed up the solution of FEM equations in real-time. Inthis way it is possible to solve the local neighborhood of the contactwith high refresh rates, while evaluating the more distant regions atlower frequencies, saving computational power to model complexbehaviour within the contact area. Solution of the different regionsusing different methods is also possible. To attain maximum efficiencythe size of the regions can be changed, in real-time, in responseto the size of the deformation.

This book and its companion volume, LNCS 7282 and 7283, constitute the refereed proceedings of the 8th International Conference, EuroHaptics 2012, held in Tampere, Finland, in June 2012. The 99 papers (56 full papers, 32 short papers, and 11 demo papers) presented were carefully reviewed and selected from 153 submissions. Part I contains the full papers whereas Part II contains the short papers and the demo papers.

For the simulation of soft tissue deformation Finite ElementMethod (FEM) has been the technique which achieves most physicallyrealistic behaviour. However to provide stable force feedback,high refresh rates are needed which makes the use of FEMnon-trivial.To solve the challenge of the compromise between speed and realism,asynchronous regions which solves different parts of the modelwith different frequencies and different resolutions are used. Thelocal neighbourhood of the contact is solved with higher frequencyand resolution while the more remote regions are solved with lowerfrequency and resolutions. Different solution methods, implicit andexplicit, can be used to solve different regions and the size of theregions can be adapted depending on the strain to maximize theefficiency.

The roles of human operators are changing due to increased intelligence and autonomy of computer systems. Humans will interact with systems at a more overarching level or only in specific situations. This involves learning new practices and changing habitual ways of thinking and acting, including reconsidering human autonomy in relation to autonomous systems. This paper describes a design case of a future autonomous management system for drone traffic in cities in a key scenario we call The Computer in Brussels. Our approach to designing for human collaboration with autonomous systems builds on scenario-based design and cognitive work analysis facilitated by computer simulations. We use a temporal method, called the Joint Control Framework to describe human and automated work in an abstraction hierarchy labeled Levels of Autonomy in Cognitive Control. We use the Score notation to analyze patterns of temporal developments that span levels of the abstraction hierarchy and discuss implications for human-automation communication in traffic management. We discuss how autonomy at a lower level can prevent autonomy on higher levels, and vice versa. We also discuss the temporal nature of autonomy in minute-to-minute operative work. Our conclusion is that human autonomy in relation to autonomous systems is based on fundamental trade-offs between technological opportunities to automate and values of what human actors find meaningful.

Drone-based services in cities will most likely result in high traffic densities (especially during peak hours). Basic unmanned/urban (air) traffic management (UTM) tools and interventions to cope with traffic issues are now well-known (e.g. geofences, layers). There can however be interdependencies between issues and solutions when combined. This paper presents sampled side-effects of using basic unmanned traffic management interventions in an airspace with autonomous point-to-point drone traffic. The samples are based on an interactive simulation and consists of statistics and synthetic images of the simulated situations. We have for instance sampled traffic proximate to a geofenced airport, and traffic from/to proximate logistics hubs. Consequences for UTM development in cities, for the European development of U-space U3 and U4, are discussed.

We believe that the lateral exploration of surfaces with varying stiffness, stiffness maps, using computer generated haptics is an underestimated and important procedure with impact in many application areas. Feeling the change of stiffness while sweeping the haptic probe over a surface can potentially give an understanding of the spatial distribution of this stiffness, however current algorithms lack tangential cues of stiffness changes. This introduces energy sources and sinks that potentially affects the stability of the system, apart from being physically incorrect and thus unrealistic. We discuss the forces and effects involved in the exploration of stiffness maps and propose an energy-based algorithm for tangential forces that augments the feedback from the map, in particular during lateral exploration. The algorithm is based on basic physical principles and has the potential to increase both realism and stability. A user study was conducted to analyze the effect of this algorithm on stiffness perception.

Haptics has in earlier work shown the potential to assist in the understanding of an otherwise overwhelming amount of information in scientific and medical visualization. In the typical scientific data, with many different properties such as pressure, temperature, strain, etc, the user is required to switch between what data to represent through the haptic feedback. In this paper we explore the possibility to simultaneously represent, in a comprehensive way, more than one property through the haptic feedback by dividing the feedback into the two components of the haptic sense. Two vibrotactile metaphors for scalar data are described, roughness and transition cue, that can be used in combination with a kinaesthetic representation of either scalar or vector data. The paper also presents an evaluation that shows that the individual cues from the two haptic metaphors can be discriminated, and that the combined feedback can be used to find combinations of features in data.

Visualization is the process of making something perceptible to the mind or imagination. The techniques for producing visual imagery of volumetric data have advanced immensely during the last decades to a point where each produced image can include an overwhelming amount of information. An increasingly viable solution to the limitations of the human sense of visual perception is to make use of not only vision, but also additional senses.

This thesis presents recent work on the development of principles and algorithms for generating representations of volumetric data through the sense of touch for the purpose of visualization. The primary idea introduced in this work is the concept of yielding constraints, that can be used to provide a continuous set of shapes as a representation of features of interest in various types of volumetric data. Some of the earlier identified standard human exploratory procedures can then be used which enables natural, intuitive and effective interaction with the data. The yielding constraints concept is introduced, and an algorithm based on haptic primitives is described, which forms a powerful yet versatile implementation of the yielding constraints. These methods are also extended to handle time-varying, moving and low quality data. A framework for multimodal visualization has been built on the presented methods, and this is used to demonstrate the applicability and versatility of the work through several example applications taken from different areas.

Volume haptics has shown itself an effective way of enhancing precision and speed in interaction with medical or scientific visualization. This paper presents a mixed solver approach for the primitive-based volume haptics problem, to provide the best performance for every volume haptics application. For situations where the constraints are orthogonal we present a fast and high precision analytical solver. For complex configurations requiring support for non-orthogonal constraints we allow for fall-back on a numerical solver. The results show significantly improved performance with the analytical solver, allowing for higher stiffness and thus feedback of higher quality, while still allowing for transparent support for non-orthogonal constraints.

As the volumes are entering the world of computer graphics the pure volume visualisation becomes a more important tool in for example research and medical applications. But the advance in haptics --- force feedback from the computer --- is behind. In volume haptics no equal to the proxy method so popular in surface haptics has yet emerged. Some implementations of volume haptics even use surfaces as intermediate representations so that surface haptics can be used.

The intention of this work was to create natural feeling haptic feedback from volumetric density data using pure volume haptics. The haptic algorithm would be implemented in Reachin API for the Reachin Desktop Display, together with other parts to build up a usable volume visualisation environment.

To achieve the feeling of stiffness and friction dependent on tissue type, a proxy based method was developed. In the volume the proxy is constrained by virtual surfaces defined by the local gradient. This algorithm was implemented in a volume haptics node and for visualisation a volume renderer node was implemented. These nodes can be used to setup different volume visualisation environments using VRML.

Volume haptics has become an increasingly popular way of adding guidance and improving information bandwidth in scientific visualization. State-of-the-art methods, however, use linear equations, which allows for a precision that can be insufficient in some circumstances. This paper describes how step-length subdivision can be used to improve precision even though these methods do not use integration steps in its usual meaning.

The ever increasing size and complexity of volumetric data in a wide range of disciplines makes it useful to augment volume visualization tools with alternative modalities. Studies have shown that introducing haptics can significantly increase both exploration speed and precision. It is also capable of conveying material properties of data and thus has great potential to improve user performance in volume data exploration. In this paper we describe how recent advances in volume haptics can be used to build haptic modes-building blocks for haptic schemes. These modes have been used as base components of a toolkit allowing for more efficient development of haptic prototypes and applications. This toolkit allows interactive construction, configuration and fine-tuning of both visual and haptic representations of the data. The technology is also used in a pilot study to determine the most important issues and aspects in haptic volume data interaction and exploration, and how the use of haptic modes can facilitate the implementation of effective haptic schemes.

This paper introduces Vector Field Perpendicular Surfaces as a means to represent vector data with special focus on variations across the vectors in the field. These surfaces are a perpendicular analogue to streamlines, with the vector data always being parallel to the normals of the surface. In this way the orientation of the data is conveyed to the viewer, while providing a continuous representation across the vectors of the field. This paper describes the properties of such surfaces including an issue with helicity density in the vector data, an approach to generating them, several stop conditions and special means to handle also fields with non-zero helicity density.

With current methods for volume haptics in scientific visualization, features in time-varying data can freely move straight through the haptic probe without generating any haptic feedback-the algorithms are simply not designed to handle variation with time but consider only the instantaneous configuration when the haptic feedback is calculated. This article introduces haptic rendering of dynamic volumetric data to provide a means for haptic exploration of dynamic behavior in volumetric data. We show how haptic feedback can be produced that is consistent with volumetric data moving within the virtual environment and with data that, in itself, evolves over time. Haptic interaction with time-varying data is demonstrated by allowing palpation of a computerized tomography sequence of a beating human heart.

Recently the constraint approach to proxy-based volume haptics was introduced which provided a stable and effective means of conveying information about volumetric data through a haptic instrument. In this paper we present a proof that the approach is incapable of handling nonorthogonal constraints and discuss the implications of this restriction in detail. We also describe how full utilization of haptics applications in which multiple properties are used to enhance the understanding of complex data requires the use of non-orthogonal constraints. We then show how proxybased volume haptics can be modified to allow for general constraints through the introduction of haptic primitives used to model the constraints. By balancing the forces exerted by the primitives on the proxy continuously, nonorthogonal constraints can be handled.

Enhancing volume visualization with additional cues from our sense of touch has shown the potential to increase both speed and accuracy in the data exploration. Research in the area display a wide array of modes of interaction and many of these have been evaluated to demonstrate their capabilities. There are, however, few studies performed that compare different approaches for their strengths and weaknesses and there is a lack of guidelines on how the haptic feedback should be designed to allow for best performance. This paper describes a study on the influence of the basic principle chosen for data representation on the ability to identify faint structures in the data. Three metaphors are compaired, two types of shape metaphors and one force metaphor. Based on statistical analysis on evaluation data, interviews and observations a set of guidelines on the design of haptic visualization is described.

We present a general, proxy-based approach to volume haptics founded upon the notion of 'haptic primitives'. Haptic modes each representing a different aspect of volumetric data, are created by defining sets of haptic primitives which reflect the local properties of the data. The proxy position for every time-frame in the haptic loop is found by balancing the force feedback in the haptic instrument with the force from the haptic primitives involved. The presented general framework allows for rapid development of haptic feedback modes for volumetric data. The approach also allows, in contrast to previous work on proxy-based volume haptics, combination of non-orthogonal constraints and thus allows free combination of various modes in haptic exploration of multivariate data. We demonstrate the effectiveness of our approach through the implementation of five different haptic modes.

Multi Remote Tower Operations (MRTO), where one ATCO has the responsibility of two airports simultaneously, have become an important means to reduce the cost for air traffic control at small regional airports in Sweden without sacrificing safety or service levels. A challenge in MRTO is to keep normal movements operational on an airport while there is busy traffic on the second airport handled by the same ATCO. Earlier work has described the potential of using a digital tower assistant (DiTA), an automation that handles the communication and monitoring of e.g. a single, simple approach and landing on an airport with an otherwise empty sky, while the ATCO needs to focus their attention on the other airport. In this paper we let two interaction designers analyse the interview material from a recent study with five experienced ATCOs, each performing two scenarios using DiTA, and present the conclusions made from an interaction design perspective.

This book constitutes the refereed proceedings of the 7th International Conference on Haptic and Audio Interaction Design, HAID 2012, held in Lund, Sweden, in August 2012. The 15 full papers presented were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on haptics and audio in navigation, supporting experiences and activities, object and interface, test and evaluation.

Haptics provides powerful cues about forces but cannot easily be integrated in all relevant applications, such as education. Pseudo-haptic cues, visual information that simulate haptic sensations, have been raised as an alternative. It is, however, largely unknown how (or even if) pseudo-haptic cues are perceived by the haptic sensory modality. In this paper we present an approach that applies theories on multimodal integration to testing if a pseudo-haptic cue is triggering haptic perception. This approach is subsequently applied in designing an experiment that tests a pseudo-haptic cue based on a visual force-causes-displacement metaphor, similar to a rubber band.

Geographic visualizations are, due to the limited need for vertical navigation,  suitable for touch tables. In this poster we consider the design of interaction design for selection and manipulation through touch on the screen used for the display of 3D geographic visualization---in our case the visualization of and interaction with drone traffic over rural and urban areas---focusing on moving from a monoscopic to a more immersive, stereoscopic touch table, and how this move affects the interaction design. With a monoscopic display our stereoscopic vision uses the graphics to perceive the location of the surface, and touch interaction can naturally and intuitively be performed on top of 3D objects. Moving to stereocopic display, for increased sense of immersion, the graphics no longer provide visual cues about the location of the screen. We argue that this motivates modification of the design principles, with an alternative interaction design as a result.

Direct volume haptics can provide both guidance and extra information during exploration of volumetric data. In this paper we present a novel approach to volume haptics enabling haptic exploration of tissue shape, borders and material properties in data despite low contrast and low signal to noise ratio, as is common in medical MRI data or low dose CT data. The method uses filtering based on implicit knowledge and addresses the problem of overlapping scalar ranges through the introduction of fuzzy classification and corresponding transfer functions for material properties as well as classification-based distance masking for haptic force direction.

Thermal imaging cameras, commonly used in application areas such as building inspection and night vision, have recently also been introduced as pedagogical tools for helping students visualize, interrogate and interpret notoriously challenging thermal concepts. In this paper we present a system for Spatial Augmented Reality that automatically projects thermal data onto objects. Instead of having a learner physically direct a hand-held camera toward an object of interest, and then view the display screen, a group of participants can gather around the display system and directly see and manipulate the thermal profile projected onto physical objects. The system combines a thermal camera that captures the thermal data, a depth camera that realigns the data with the objects, and a projector that projects the data back. We also apply a colour scale tailored for room temperature experiments.

Recent research shows that infrared cameras can help students visualize and interpret notoriously challenging thermal concepts. This chapter describes the application of thermal visualization in a public setting. Specifically, we present the design and implementation of an augmented reality system for the real-time projection of thermal imagery onto objects. Examples of hands-on activities for visualizing thermal processes with the system include conduction and insulation, rubber band thermodynamics, friction, impact heating, enthalpy of chemical reactions, radiation wavelength, mixing liquids, and heat of evaporation. We discuss how the interactive activities might provide pedagogical opportunities for accessing and engaging with thermal phenomena in a science center context. Practical considerations of the system for public exhibition spaces are also given attention.

Datasets from Computational Fluid Dynamics (CFD) can be post-processed and visualized to aid understanding of the flow phenomena present. Visualization of CFD data, however, often suffers from problems such as occlusion and cluttering when methods such as glyphing and volume rendering are applied. In this paper we present a case study where new modes for haptic interaction are used to enhance the exploration of CFD data. A VR environment with interactive graphics and an integrated graphical user interface has been implemented. In contrast to previous work on haptic interaction with CFD data we employ a 'reactive' haptic scheme as opposed to direct force maping. The reactive approach not only generates more stable feedback but also provides clearer and more intuitive cues about the underlying data. Two haptic modes are used to enhance the understanding of different features in the flow data: One presents the orientation of the data and also guides the user to follow the stream as it flows around the aircraft fuselage. The other provides a haptic representation of vortex data. This mode enables the user to perceive and so follow tendencies of vorticity and vortices.

Drone traffic, consisting of anything from small quadcopters for video and photography to large eVTOL transporting people, is expected to grow rapidly as soon as the challenges currently barring urban flights can be solved. One of the main challenges is how to automate authorization while both keeping full control over where and how drones fly over specific areas, and at the same time allowing the operators the freedom they require to successfully provide their services. While restrictions are necessary, being overly restrictive on plans has a negative impact on capacity, safety and efficiency. In this article we propose the combination of no-fly zones and flight grids into design elements for airspace design, to be used only where and when necessary. City planners can use these design elements to make both strategic decisions and real-time updates, and thereby set the rules for an automated system for planning and authorization. We describe the design elements, how to automatically find the optimal end-to-end route between or through these elements, a set of modifications or extension to improve flexibility even more, and demonstrate the efficacy of the approach through example airspace design patterns and by showing the resulting traffic in a drone traffic simulator.

In this paper a new approach to volume haptics is presented. The developed method makes use of a proxy that is constrained by ‘virtual surfaces’, defined by the local gradient at the proxy position, and not by iso-values as in other approaches to volume haptics. By using a proxy, material properties like friction, stiffness and surface penetrability can be implemented. These material properties are controlled by user defined transfer functions. At the same time, using the gradient to define surfaces, rendering of infinitesimally close virtual surfaces that can be penetrated, is made possible. The algorithm exhibits very high stability, is fast and represents fine details accurately. Compared to earlier techniques, less artifacts occur and higher configurability is provided.