A Survey of Interaction Techniques and Devices for Large High Resolution Displays

Innovations in large high-resolution wall-sized displays have been yielding benefits to visualizations in industry and academia, leading to a rapidly growing increase of their implementations. In scenarios such as these, the displayed visual information tends to be larger than the users field of view, hence the necessity to move away from traditional interaction methods towards more suitable interaction devices and techniques. This paper aspires to explore the state-of-the-art with respect to such technologies for large high-resolution displays

Assessing 3D Scan Quality Through Paired-comparisons Psychophysics

ABSTRACT Consumer 3D scanners and depth cameras are increasingly being used to generate content and avatars for Virtual Reality (VR) environments and avoid the inconveniences of hand modeling; however, it is sometimes difficult to evaluate quantitatively the mesh quality at which consumer available 3D scans should be exported, and whether the object perception might be affected by its shading. We propose using a paired-comparisons test based on psychophysics of perception to do that evaluation. As psychophysics is not subject to opinion, skill level, mental state, or economic situation it can be considered a quantitative way to measure how people perceive the mesh quality. In particular, we compare four different levels of mesh quality (1K, 5K, 10K and 20K triangles). We present two studies within subjects: in one we investigate the influences of seeing an object in a regular screen vs. in a Head Mounted Display (HMD); while in the second experiment we aim at detecting the effects of shading into quality perception. At each iteration of the pair-test comparisons participants pick the mesh that they think had higher quality; by the end of the experiment we compile a preference matrix. The results show a correlation between real and assessed quality, despite participants' reported uncertainty. We also find an interaction with quality and shading, which gains importance for quality perception when the mesh has high definition. Furthermore, we assess the subjective realism of the most/least preferred scans using an Immersive Augmented Reality (IAR) video-see-through setup to compare the real vs the 3D scanned object in the same HMD environment. Results show higher levels of realism were perceived through the HMD than when using a regular monitor, although the quality was similarly perceived in both systems

Mesh generation for voxel -based objects

A new physically-based approach to unstructured mesh generation via Monte-Carlo simulation is proposed. Geometrical objects to be meshed are represented by systems of interacting particles with a given interaction potential. A new way of distributing nodes in complex domains is proposed based on a concept of dynamic equilibrium ensemble, which represents a liquid state of matter. The algorithm is simple, numerically stable and produces uniform node distributions in domains of complex geometries and different dimensions. Well-shaped triangles or tetrahedra can be created by connecting a set of uniformly-spaced nodes. The proposed method has many advantages and potential applications.;The new method is applied to the problem of meshing of voxel-based objects. By customizing system potential energy function to reflect surface features, particles can be distributed into desired locations, such as sharp corners and edges. Feature-preserved surface mesh can then be constructed by connecting the node set.;A heuristic algorithm using an advancing front approach is proposed to generate triangulated surface meshes on voxel-based objects. The resultant surface meshes do not inherit the anisotropy of the underlying hexagonal grid. However, the important surface features, such as edges and corners may not be preserved in the mesh.;To overcome this problem, surface features such as edges, corners need to be detected. A new approach of edge capturing is proposed and demonstrated. The approach is based on a Laplace solver with incomplete Jacobi iterations, and as such is very simple and efficient. This edge capturing approach combined with the mesh generation methods above forms a simple and robust technique of unstructured mesh generation on voxel-based objects.;A graphical user interface (GUI) capable of complex geometric design and remote simulation control was implemented. The GUI was used in simulations of large fuel-cell stacks. It enables one to setup, run and monitor simulations remotely through secure shell (SSH2) connections. A voxel-based 3D geometrical modeling module is built along with the GUI. The flexibility of voxel-based geometry representation enables one to use this technique for both geometric design and visualization of volume data

Sanal heykeltraşlıkta optimize edilmiş hash-temelli octree veri yapısının kullanılması

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Sanal heykeltıraşlık, kullanıcılara sanat, tasarım ve hızlı prototipleme alanlarında sanal gerçeklik donanım ve yazılımları tarafından sağlanan bir sanal dünya içerisinde yeni 3B katı nesne oluşturma veya mevcut nesneleri değiştirebilme imkânı sağlayan 3B bir modelleme işlemidir. Bu tez çalışmasında haptic kuvvet geri-beslemesi ile voksel-temelli bir sanal heykeltıraşlık uygulaması için optimize edilmiş hash-temelli bir octree veri yapısı kullanımı önerilmektedir. Amaç, hacim voksel veri kümesini saklamak için gerekli hafızayı ve hesaplama maliyetini düşürmek, aynı zamanda da gerçek-zamanda etkileşim esnasında gerçekleşen octree kullanımından doğan ağaç dolanım süresini azaltarak model yüzeyinin lokal olarak yeniden oluşturulma süresini kısaltmaktır. İlk önce, üzerinde çalışılan sanal ham maddeye ait hacim verisi daha az hafıza kullanarak saklayabilmek ve gerçek-zamanda yontabilmek amacıyla vokselleştirilerek optimize-edilmiş hash-temelli bir octree veri yapısına dönüştürülmektedir. Daha sonra, küre olarak tasarlanan sanal araç tarafından heykelin hangi voksellerine dokunulduğu belirlenerek bu vokseller veri yapısından çıkarılmaktadır. Sonuç verisine gerçekçi bir görüntü verebilmek amacıyla üçgen kafes modelini yeniden oluşturmak için Marching Cubes algoritması kullanılmaktadır. Tüm hacim için hesaplama maliyeti yüksek olduğundan dolayı bu çalışmada sadece yontma işleminden sonra modifiye edilen vokseller tarafından etkilenen eş yüzey yeniden hesaplanarak lokal güncelleme gerçekleştirildi. İkinci olarak, önerilen sanal heykeltıraşlık sistemine, sanal yontma aracının üç-boyutlu kontrolünü sağlamak ve kullanıcıların yontma işlemi sırasında heykel üzerinde uyguladıkları kuvvete karşı meydana gelen direnci hissedebilmelerine imkan sağlamak amacıyla bir haptic cihazı yolu ile haptic kuvvet-geri beslemesi entegre edilmiştir. Sanal heykeltıraşlıkta hafıza optimizasyonu ve gerçek-zaman etkileşimi üzerine odaklanılan bu çalışmada, önerilen optimize edilmiş hash-temelli octree veri yapısının performansını test etmek amacıyla hafıza maliyetleri ve çalışma süreleri, işaretçi-temelli ve hash temelli veri yapıları ile karşılaştırılmıştır. Sonuç olarak, bu yeni optimize edilmiş hash-temelli octree veri yapısının hem ön-işleme zamanında hem de gerçek zamanda hafıza maliyetleri ve çalışma sürelerindeki düşüşler gösterilmiştir. Anahtar kelimeler: Sanal Heykeltaşlık, Haptics, Vokselleştirme, Octree, HashingVirtual sculpting is a 3D modelling process which allows users to create new 3D solid models or modify existing objects provided by virtual reality software and hardware in art, design and rapid prototyping areas. In this thesis, an optimized hash-based octree data structure in a voxel-based virtual sculpting application with haptic force feedback is proposed. The goal is to reduce the memory and computation costs to store volumetric voxel dataset and also to reduce the local surface reconstruction times of the model by decreasing tree traversal time caused by octree during real-time interaction. First, in order to store with less memory and carve in real-time, volumetric data of virtual workpiece is converted into an optimized hash-based octree data structure by voxelizing them. Then, voxels collided with the carving tool that is designed as a sphere are removed from this data structure. Marching Cubes algorithm is used to reconstruct the triangular mesh model in order to give a realistic display of the voxel data. Since the computational cost is very high for the whole volume, in this study, local update is performed by reconstructing the isosurface affected from the modified voxels after carving process. Afterwards, by the way of a haptic device, a haptic force feedback is integrated in the proposed virtual sculpting application in order to provide 3D control of the virtual tool and allow to feel the resistance against the applied force on the sculpture object. This study focused on memory optimization and real-time interaction, memory costs and runtimes of the proposed optimized hash-based octree data structure are compared with the pointer-based and hash-based ones in order to test the performance. Consequently, memory cost and working time decreases on both pre-processing and runtime of this new optimized hash-based octree data structure are shown. Keywords: Virtual Sculpting, Haptics, Voxelization, Octree, Hashin

Real-time hybrid cutting with dynamic fluid visualization for virtual surgery

It is widely accepted that a reform in medical teaching must be made to meet today's high volume training requirements. Virtual simulation offers a potential method of providing such trainings and some current medical training simulations integrate haptic and visual feedback to enhance procedure learning. The purpose of this project is to explore the capability of Virtual Reality (VR) technology to develop a training simulator for surgical cutting and bleeding in a general surgery

Towards a digitally conceived physical performance object

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2007.Includes bibliographical references (p. 122-126).In the performing arts, the relationship that is established between what is seen and what is heard must be experienced to fully appreciate and understand the aesthetics of performance. Actual physical objects such as musical instruments, lights, elements of the set, props, and people provide the visual associations and a tangible reality which can enhance the musical elements in a performance. This thesis proposes that new and artistic physical objects can, in themselves, be designed to perform. It introduces the Chandelier, a kinetic sculpture, a central set piece for a new opera, a new kind of musical instrument, and an object that performs. The piece moves and changes shape through mechanical action and the designed interplay between surfaces and light. It is intended to be interacted with by musicians and players of the opera. This thesis also explores the design process and evolution of the Chandelier with a primary objective of realizing a constructible, physical performance object through an authentic and abstruse digital conception. It is a conception not of a static nature, but incorporates a dynamic sense of changeable form through coordinated elements of light, mechanics, and sculpture.Steven L. Pliam.S.M

Wizualizacja zjawisk topnienia i sublimacji

Niniejsza monografia dotyczy wizualizacji zjawisk topnienia i sublimacji, które są przejściem fazowym z ciała stałego odpowiednio do cieczy i gazu. Modelem granicy miedzy dwoma fazami jest powierzchnia międzyfazowa, dlatego topnienie i sublimacja mogą być rozpatrywane jako przesuwanie powierzchni międzyfazowej z towarzysząca mu wymiana ciepła. Wizualizacja omawianych zjawisk wymaga omówienia różnych jej aspektów – od sposobu reprezentacji danych graficznych, przez algorytmy przetwarzania tych danych i ich optymalizacje, problemy renderingu czasu rzeczywistego, po metody weryfikacji jej wyników. Wymienione kwestie zostały zebrane w niniejszej ksiażce