Currently, both understanding and developing interactive visual interfaces become ever more challenging, since different visual solutions exist that involve large interdisciplinary teams and deal with massive amounts of data, a wide range of interaction techniques, and domain-specific aspects. At the same time, traditional design methods become obsolete with more and more resources and knowledge that needs to be acquired. The proposed workshop provides a forum for discussing experimental and theoretical techniques, frameworks, and prototyping methods to design visual interfaces in different domains such as data visualization, tangible and embedded interaction, extended and mixed reality, multi-modal interfaces, and others.

Abstract Interactions within virtual environments often require manipulating 3D virtual objects. To this end, researchers have endeavoured to find efficient solutions using either traditional input devices or focusing on different input modalities, such as touch and mid‐air gestures. Different virtual environments and diverse input modalities present specific issues to control object position, orientation and scaling: traditional mouse input, for example, presents non‐trivial challenges because of the need to map between 2D input and 3D actions. While interactive surfaces enable more natural approaches, they still require smart mappings. Mid‐air gestures can be exploited to offer natural manipulations mimicking interactions with physical objects. However, these approaches often lack precision and control. All these issues and many others have been addressed in a large body of work. In this article, we survey the state‐of‐the‐art in 3D object manipulation, ranging from traditional desktop approaches to touch and mid‐air interfaces, to interact in diverse virtual environments. We propose a new taxonomy to better classify manipulation properties. Using our taxonomy, we discuss the techniques presented in the surveyed literature, highlighting trends, guidelines and open challenges, that can be useful both to future research and to developers of 3D user interfaces.

A fundamental step in medical diagnosis for patient follow-up relies on the ability of radiologists to perform a trusty diagnostic from acquired images. Basically, the diagnosis strongly depends on the visual inspection over the shape of the lesions. As datasets increase in size, such visual evaluation becomes harder. For this reason, it is crucial to introduce easy-to-use interfaces that help the radiologists to perform a reliable visual inspection and allow the efficient delineation of the lesions. We will explore the radiologist's receptivity to the current touch environment solution. The advantages of touch are threefold: (i) the time performance is superior regarding the traditional use, (ii) it has more intuitive control and, (iii) for less time, the user interface delivers more information per action, concerning annotations. From our studies, we conclude that the radiologists still exhibit a resistance to change from traditional to touch based interfaces in current clinical setups.

Context-aware pervasive applications can improve user experiences by tracking people in their surroundings. Such systems use multiple sensors to gather information regarding people and devices. However, when developing novel user experiences, researchers are left to building foundation code to support multiple network-connected sensors, a major hurdle to rapidly developing and testing new ideas.

Virtual Reality environments are able to offer natural interaction metaphors. However, it is difficult to accurately place virtual objects in the desired position and orientation using gestures in mid-air. Previous research concluded that the separation of degrees-of-freedom (DOF) can lead to better results, but these benefits come with an increase in time when performing complex tasks, due to the additional number of transformations required. In this work, we assess whether custom transformation axes can be used to achieve the accuracy of DOF separation without sacrificing completion time. For this, we developed a new manipulation technique, MAiOR, which offers translation and rotation separation, supporting both 3-DOF and 1-DOF manipulations, using personalized axes for the latter. Additionally, it also has direct 6-DOF manipulation for coarse transformations, and scaled object translation for increased placement. We compared MAiOR against an exclusively 6-DOF approach and a widget-based approach with explicit DOF separation. Results show that, contrary to previous research suggestions, single DOF manipulations are not appealing to users. Instead, users favored 3-DOF manipulations above all, while keeping translation and rotation independent.

Several studies have shown the suitability of the direct manipulation style and the multi-touch technology for kindergarteners and, as a result, direct dragging has been established as the standard way of interaction when supporting drag manipulations for them. However, there are scenarios in which direct dragging is not appropriate. For example, when the object to be dragged has to move at a fixed speed or performing an animation independent of the actual direct movement speed or trajectory of the user's hand. However, nobody has yet explored the suitability of indirect dragging interaction mechanisms that allow designers to effectively implement these scenarios. This paper evaluates different mechanisms of indirect dragging manipulations (Tap-based, Accelerometer-based and Buttons-based) in order to identify those that could be used by kindergarteners in scenarios where the direct dragging is not suitable. The results show that even though kindergarten children are able to effectively use different types of indirect dragging techniques, some considerations in terms of completion time and precision must be taken into account.

Travel on Virtual Environments is the simple action where a user moves from a starting point A to a target point B. Choosing an incorrect type of technique could compromise the Virtual Reality experience and cause side effects such as spatial disorientation, fatigue and cybersickness. The design of effective travelling techniques demands to be as natural as possible, thus real walking techniques presents better results, despite their physical limitations. Approaches to surpass these limitations employ techniques that provide an indirect travel metaphor such as point-steering and target-based. In fact, target-based techniques evince a reduction in fatigue and cybersickness against the point-steering techniques, even though providing less control. In this paper we investigate further effects of speed and transition on target-based techniques on factors such as comfort and cybersickness using a Head-Mounted Display setup.

Object manipulation is a key feature in almost every virtual environment. However, it is difficult to accurately place an object in immersive virtual environments using mid-air gestures that mimic interactions in the physical world, although being a direct and natural approach. Previous research studied mouse and touch based interfaces concluding that separation of degrees-of-freedom (DOF) led to improved results. In this paper, we present the first user evaluation to assess the impact of explicit 6 DOF separation in mid-air manipulation tasks. We implemented a technique based on familiar virtual widgets that allow single DOF control, and compared it against a direct approach and PRISM, which dynamically adjusts the ratio between hand and object motions. Our results suggest that full DOF separation benefits precision in spatial manipulations, at the cost of additional time for complex tasks. From our results we draw guidelines for 3D object manipulation in mid-air.

Query specification for 3D object retrieval still relies on traditional interaction paradigms. The goal of our study was to identify the most natural methods to describe 3D objects, focusing on verbal and gestural expressions. Our case study uses LEGO R blocks. We started by collecting a corpus involving ten pairs of subjects, in which one participant requests blocks for building a model from another participant. This small corpus suggests that users prefer to describe 3D objects verbally, rarely resorting to gestures, and using them only as complement. The paper describes this corpus, addressing the challenges that such verbal descriptions create for a speech understanding system, namely the long complex verbal descriptions, involving dimensions, shapes, colors, metaphors, and diminutives. The latter connote small size, endearment or insignificance, and are only very common in informal language. In this corpus, they occurred in one out of seven requests. This experiment was the first step of the development of a prototype for searching LEGO R blocks combining speech and stereoscopic 3D. Although the verbal interaction in the first version is limited to relatively simple queries, its combination with immersive visualization allows the user to explore query results in a dataset with virtual blocks. Index Terms: multimodal corpus, 3D objects, voice search

The growing number of three-dimensional (3D) objects stored in digital libraries brought forth the challenge of search in 3D model collections. To address it, several approaches have been developed for 3D object retrieval. However, these approaches traditionally present query results as a list of thumbnails, and fail to take advantage of recent visualization and interaction technologies. In this paper, we propose an approach to 3D object retrieval using immersive VR for query result visualization. Query results are shown in a three-dimensional virtual space as 3D objects and users can explore these results by navigating in this virtual space and manipulating the scattered objects.