1,460 research outputs found

    An Introduction to 3D User Interface Design

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    3D user interface design is a critical component of any virtual environment (VE) application. In this paper, we present a broad overview of three-dimensional (3D) interaction and user interfaces. We discuss the effect of common VE hardware devices on user interaction, as well as interaction techniques for generic 3D tasks and the use of traditional two-dimensional interaction styles in 3D environments. We divide most user interaction tasks into three categories: navigation, selection/manipulation, and system control. Throughout the paper, our focus is on presenting not only the available techniques, but also practical guidelines for 3D interaction design and widely held myths. Finally, we briefly discuss two approaches to 3D interaction design, and some example applications with complex 3D interaction requirements. We also present an annotated online bibliography as a reference companion to this article

    Vision-Based Three Dimensional Hand Interaction In Markerless Augmented Reality Environment

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    Kemunculan realiti tambahan membolehkan objek maya untuk wujud bersama dengan dunia sebenar dan ini memberi kaedah baru untuk berinteraksi dengan objek maya. Sistem realiti tambahan memerlukan penunjuk tertentu, seperti penanda untuk menentukan bagaimana objek maya wujud dalam dunia sebenar. Penunjuk tertentu mesti diperolehi untuk menggunakan sistem realiti tambahan, tetapi susah untuk seseorang mempunyai penunjuk tersebut pada bila-bila masa. Tangan manusia, yang merupakan sebahagian dari badan manusia dapat menyelesaikan masalah ini. Selain itu, tangan boleh digunakan untuk berinteraksi dengan objek maya dalam dunia realiti tambahan. Tesis ini membentangkan sebuah sistem realiti tambahan yang menggunakan tangan terbuka untuk pendaftaran objek maya dalam persekitaran sebenar dan membolehkan pengguna untuk menggunakan tangan yang satu lagi untuk berinteraksi dengan objek maya yang ditambahkan dalam tiga-matra. Untuk menggunakan tangan untuk pendaftaran dan interaksi dalam realiti tambahan, postur dan isyarat tangan pengguna perlu dikesan. The advent of augmented reality (AR) enables virtual objects to be superimposed on the real world and provides a new way to interact with the virtual objects. AR system requires an indicator to determine for how the virtual objects aligned in the real world. The indicator must first be obtained to access to a particular AR system. It may be inconvenient to have the indicator in reach at all time. Human hand, which is part of the human body may be a solution for this. Besides, hand is also a promising tool for interaction with virtual objects in AR environment. This thesis presents a markerless Augmented Reality system which utilizes outstretched hand for registration of virtual objects in the real environment and enables the users to have three dimensional (3D) interaction with the augmented virtual objects. To employ the hand for registration and interaction in AR, hand postures and gestures that the user perform has to be recognized

    Control and manipulation of nanoparticles for fabrication of metal matrix composites

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    The mechanical properties of composite materials are mainly determined by their microstructures that depend on comprising phases and their properties, the shape and size of those phases, and their distribution. By controlling and optimizing the various aspects of the microstructure, composites with improved mechanical properties can be created. One of the challenges, however, is the lack of scalable fabrication method capable of making complex structures. The conventional fabrication techniques for MMCs have been limited to fabricating simple structures with homogeneous dispersion of constituents. In this work, various fabrication approaches that can control the microstructure in metal matrix reinforced with nanoparticles have been studied. Mechanical alloying (ball milling) was used to control the dispersion of graphene sheets in homogeneous reinforced aluminum composites. Spray assisted deposition of nanoparticles was used to fabricate layered composites with uniformly and hierarchically reinforced interfaces. Magnetic field assisted deposition was studied to manipulate and deposit nanoparticles into micro-patterns that can be used to create hierarchically layered composites. Homogeneously reinforced aluminum alloy (Al6061) reinforced composites with graphene have been synthesized using mechanical alloying followed by semisolid sintering. The ball milling was used to control the dispersion as well as the cluster size of the graphene within the matrix. The effect of ball milling time on the fabricated composites was studied. A significant enhancement in the mechanical properties of the graphene reinforced composites was observed compared with the matrix material processed at the same condition. Layered composites, which are uniformly or hierarchically reinforced at the interfaces, have been synthesized by implementing two processing concepts: spray assisted deposition and metallurgy (semi-solid sintering). Ultrasonic spray deposition creates nano-/micro-/meso-scale patterns on metallic sheets, which are then stacked together, densified, and synthesized into a composite through pressure assisted semi-solid sintering process. Silicon carbide (SiC) nanoparticle reinforced lightweight alloys (i.e. Magnesium Alloy (AZ31) and Al6061) have been synthesized. The synthesized composites showed an improvement in the strength with minor decrease on the total elongation. Magnetic field directed manipulation of nanoparticles was demonstrated to self-assemble and deposit nanoparticles into user-defined micro-patterns on Al substrate for potential use in synthesis of hierarchically structure layered composites. The magnetic field was modulated by machining (e.g. micro-milling and laser machining) user-defined pattern of protrusions on the magnetic source surface. The deposition of magnetic particles as well as mixtures of magnetic and nonmagnetic nanoparticles was studied
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