Engineering

The concepts of immersion and presence focus on the environment in a virtual environment. We instead focus on embodied conversational agents (ECAs). ECAs occupy the virtual environment as interactive partners. We propose that the ECA analogues of immersion and presence are physicality and social presence.

Models of human motor behavior are well known as an aid in the design of user interfaces (UIs). Most current models apply primarily to desktop interaction, but with the development of non-desktop UIs, new types of motor behaviors need to be modeled. Distal pointing-pointing directly at a target that is remotely situated with respect to the input device-is such a motor behavior. A model of distal pointing would be particularly useful in the comparison of different interaction techniques, because the performance of such techniques is highly dependent on user strategy, making controlled studies difficult to perform. Inspired by Fitts' law, we studied four possible models and concluded that movement time for a distal pointing task is best described as a function of the angular amplitude of movement and the angular size of the target. Contrary to Fitts' law, our model shows that the angular size has a much larger effect on movement time than the angular amplitude and that the growth in the difficulty of the tasks is quadratic, rather than linear. We estimated the model's parameters experimentally with a correlation coefficient of 96%.

The project Çatalhöyük @ DiVE seeks to produce new interpretations of the Neolithic site of Çatalhöyük (Turkey) through the immersive simulation at DiVE (Duke immersive Virtual Environment), a six-channel CAVE virtual reality system. The excavation and digital documentation of the mud brick Neolithic house Building 89 (B89) have produced rich datasets of archaeological data including drawings, pictures, videos, terrestrial laser scanning data, image-based 3D models, spatial analysis data, ground-penetrating radar data, and metadata (Forte et al 2012). The immersive visualization at DiVE enhances the interpretation of the phases related to the life and abandonment of B89 allowing users to visualize and interact with 1:1 scale high resolution 3D models representing each excavated stratigraphic unit of the building. Our approach seeks to clarify whether the interpretation of B89 is enhanced by the possibility to employ cyber archaeological tools in the simulation of the excavation. Specifically the simulation of B89 at DiVE benefits of the following tools: clipping planes that cut through layers and emphasize cross-sections not visible in reality, in-context menus to toggle different layers, in-context windows to superimpose archeological data on the models of the stratigraphic units, volumetric visualization of each unit, graphics shaders that enhance the visualization of texture, composition, and color of the layers. The significance of our work relies on the possibility to enable archaeologists to perceive and analyze the depositional and post-depositional phases of B89 using a cyber-approach that integrates a plurality of data in a single simulation environment that is not limited by reality constraints.

Remote sensing data capture and virtual reality visualization have changed the archaeological documentation and interpretation of the Neolithic site of Çatalhöyük, located in the Konya province in Turkey (Berggren et al. forthcoming 2015). Indeed, since 2011, the ongoing excavation and digital documentation of the mud brick house Building 89 (B89) have produced a large amount of remote sensing data including representations of all the excavated stratigraphic layers as well as Ground Penetrating Radar prospections, and a number of digitized finds. Remarkably, nighty-eight high resolution 3D models of excavated layers have been generated so far via image-based modeling techniques—using an 18 megapixel Canon DSLR camera and Agisoft Photoscan—along with a similar number of colored point clouds recorded through a FARO Focus 3D shift-phase Terrestrial Laser. This unique dataset is a great resource for the interpretation of the material culture of Çatalhöyük as well as a great methodological challenge for virtual reality (VR) inquiry in archaeology. To provide viable solutions to this challenge, we designed and developed a scalable virtual reality application able to foster archaeological data analysis and interpretation in a realistic and highly interactive virtual environment deployable in an array of different systems. In fact, our VR application exploits the flexibility of a powerful game development ecosystem, such as Unity 3D, and enhances the perception and interaction with data via stereoscopic visualization, motion tracking techniques, and new commodity VR devices. Specifically, our application can be deployed as follows: desktop immersive VR based on a Z-Space interactive stereo display; portable VR based on Oculus Rift head-mounted display and Hydra Razer two-handed 3D controller; high-end immersive VR based on a six-channel CAVE—the Duke immersive Virtual Environment running on a PC cluster with high-end motion capture capability. In terms of data visualization, our application presents three different modes: micro scene visualizing the stratigraphy and finds of B89; reconstruction visualizing a hypothetic virtual reconstruction of B89 before abandonment; macro scene visualizing the context of B89 via a Digital Elevation Model of Çatalhöyük East Mound and a number of excavated Neolithic buildings surrounding B89. The analysis of the archaeological data of B89 and nearby buildings is enhanced by database queries that can be executed directly within the virtual environment, making the 3D models a spatial interface to Çatalhöyük database. In addition, our application enhances the interpretation of B89 through custom VR tools as follows: in-context menus used to toggle different layers; in-context windows used to visualize photographs and drawings within the virtual environment; cross-section planes able to cut through layers; 3D annotation tools; volumetric visualization of each unit; graphics shaders that enhance texture, composition, and color of layers. The significance of our work relies on a cyber-approach to archaeology that integrates a plurality of data in a single simulation environment not limited by reality constraint where advanced interactive techniques simulates the depositional and post-depositional phases of B89 and its archaeological context.

The project Çatalhöyük @ DiVE started in 2013 as a multidisciplinary research collaboration initiative between Dig@Lab and DiVE at Duke University. Dig@Lab is the new digital archaeology facility at Duke University—directed by Prof. Maurizio Forte—focused on investigating how the information is shaped, elaborated, stored and then culturally transmitted by different societies, with a focus on ancient civilizations. The Duke immersive Virtual Environment (DiVE) is a research and education facility—directed by Dr. Regis Kopper—committed to exploring techniques of immersive virtual reality and interaction in a six-channel CAVE (Cave Automatic Virtual Environment) in a variety of scientific fields. Çatalhöyük @ DiVE seeks to make available to the Duke community and the general public a 1:1 scale, immersive representation of a mud brick Neolithic house (Building 89) that has been excavated in the archaeological site of Çatalhöyük, in the province of Konya in Central Anatolia, Turkey since 2011 (see Fig.1). The digital documentation process we employed in the excavation of Building 89 has produced a rich set of multimodal information including terrestrial laser scanning data, ground penetrating radar data (GPR), image-based 3D models, GIS, drawings, digital drawings, pictures, stereo-videos, and metadata. In the last 3 years these data have been employed to generate high resolution 3D models of Building 89 (i.e. over 500.000 polygons per model) using different techniques such as image-based modeling, point cloud post-processing, and manual 3D modeling in Autodesk Maya and Pixologic ZBrush. The models generated via image-based modeling and 3D modeling proved the most practical to be imported into the DiVE and be experienced by visitors and students.  More specifically, the exploration of the reconstructed space of Building 89 in an immersive virtual reality environment—featuring 6 projector screens, stereoscopic glasses, and motion tracking of the main user—allowed scholars and students to perceive the remains of the Neolithic house feeling a deep sense of presence and cognitional involvement in the place. Thanks to the immersive visualization at the DiVE, archaeologists and students can now experience and study the Neolithic Building 89 excavated at Çatalhöyük as if they were actually on site in Turkey without leaving Durham—in North Carolina, United States—in a risk-free environment. Thus this opportunity augments the pedagogical value of Duke undergraduate and graduate courses in archaeology and cultural visualization without charging the university with travel-related expenses. In addition the archaeological interpretation of Building 89 in the DiVE is enhanced by a number of cutting-edge features as follows: in-context stratigraphic layers menus that allow users to toggle different models and archeological features while interacting with the 3D scene (see Fig.2), volumetric visualization of the excavated areas showing the volume of dirt that has been removed from each layer, graphics shaders to enhance the visualization of contrast, texture, and materials, first-hand interaction with the models via  a wireless wand device. A virtual anastylosis of Building 89, showing how the building looked like before being abandoned, has also been added to the simulation in the DiVE with the goal to allow users to better comprehend prehistoric architecture and lifestyle.