20 research outputs found
Coarse-grained Multiresolution Structures for Mobile Exploration of Gigantic Surface Models
We discuss our experience in creating scalable systems for distributing
and rendering gigantic 3D surfaces on web environments and
common handheld devices. Our methods are based on compressed
streamable coarse-grained multiresolution structures. By combining
CPU and GPU compression technology with our multiresolution
data representation, we are able to incrementally transfer, locally
store and render with unprecedented performance extremely
detailed 3D mesh models on WebGL-enabled browsers, as well as
on hardware-constrained mobile devices
Mobile graphics: SIGGRAPH Asia 2017 course
Peer ReviewedPostprint (published version
Scalable exploration of highly detailed and annotated 3D models
With the widespread availability of mobile graphics terminals andWebGL-enabled browsers, 3D
graphics over the Internet is thriving. Thanks to recent advances in 3D acquisition and modeling
systems, high-quality 3D models are becoming increasingly common, and are now potentially
available for ubiquitous exploration.
In current 3D repositories, such as Blend Swap, 3D Café or Archive3D, 3D models available for
download are mostly presented through a few user-selected static images. Online exploration is
limited to simple orbiting and/or low-fidelity explorations of simplified models, since photorealistic
rendering quality of complex synthetic environments is still hardly achievable within the
real-time constraints of interactive applications, especially on on low-powered mobile devices or
script-based Internet browsers.
Moreover, navigating inside 3D environments, especially on the now pervasive touch devices,
is a non-trivial task, and usability is consistently improved by employing assisted navigation
controls. In addition, 3D annotations are often used in order to integrate and enhance the visual
information by providing spatially coherent contextual information, typically at the expense of
introducing visual cluttering.
In this thesis, we focus on efficient representations for interactive exploration and understanding
of highly detailed 3D meshes on common 3D platforms. For this purpose, we present several
approaches exploiting constraints on the data representation for improving the streaming and
rendering performance, and camera movement constraints in order to provide scalable navigation
methods for interactive exploration of complex 3D environments.
Furthermore, we study visualization and interaction techniques to improve the exploration
and understanding of complex 3D models by exploiting guided motion control techniques to aid
the user in discovering contextual information while avoiding cluttering the visualization.
We demonstrate the effectiveness and scalability of our approaches both in large screen museum
installations and in mobile devices, by performing interactive exploration of models ranging
from 9Mtriangles to 940Mtriangles
Scalable exploration of 3D massive models
Programa Oficial de Doutoramento en Tecnoloxías da Información e as Comunicacións. 5032V01[Resumo] Esta tese presenta unha serie técnicas escalables que avanzan o estado da arte da creación e exploración de grandes modelos tridimensionaies. No ámbito da xeración
destes modelos, preséntanse métodos para mellorar a adquisición e procesado de
escenas reais, grazas a unha implementación eficiente dun sistema out- of- core de
xestión de nubes de puntos, e unha nova metodoloxía escalable de fusión de datos
de xeometría e cor para adquisicións con oclusións. No ámbito da visualización de
grandes conxuntos de datos, que é o núcleo principal desta tese, preséntanse dous
novos métodos. O primeiro é unha técnica adaptabile out-of-core que aproveita o
hardware de rasterización da GPU e as occlusion queries para crear lotes coherentes
de traballo, que serán procesados por kernels de trazado de raios codificados en
shaders, permitindo out-of-core ray-tracing con sombreado e iluminación global. O segundo
é un método de compresión agresivo que aproveita a redundancia xeométrica
que se adoita atopar en grandes modelos 3D para comprimir os datos de forma
que caiban, nun formato totalmente renderizable, na memoria da GPU. O método
está deseñado para representacións voxelizadas de escenas 3D, que son amplamente
utilizadas para diversos cálculos como para acelerar as consultas de visibilidade na
GPU. A compresión lógrase fusionando subárbores idénticas a través dunha transformación
de similitude, e aproveitando a distribución non homoxénea de referencias
a nodos compartidos para almacenar punteiros aos nodos fillo, e utilizando unha
codificación de bits variable. A capacidade e o rendemento de todos os métodos
avalíanse utilizando diversos casos de uso do mundo real de diversos ámbitos e
sectores, incluídos o patrimonio cultural, a enxeñería e os videoxogos.[Resumen] En esta tesis se presentan una serie técnicas escalables que avanzan el estado del arte de la creación y exploración de grandes modelos tridimensionales. En el ámbito de
la generación de estos modelos, se presentan métodos para mejorar la adquisición y
procesado de escenas reales, gracias a una implementación eficiente de un sistema
out-of-core de gestión de nubes de puntos, y una nueva metodología escalable de
fusión de datos de geometría y color para adquisiciones con oclusiones. Para la
visualización de grandes conjuntos de datos, que constituye el núcleo principal de
esta tesis, se presentan dos nuevos métodos. El primero de ellos es una técnica
adaptable out-of-core que aprovecha el hardware de rasterización de la GPU y las
occlusion queries, para crear lotes coherentes de trabajo, que serán procesados por
kernels de trazado de rayos codificados en shaders, permitiendo renders out-of-core
avanzados con sombreado e iluminación global. El segundo es un método de compresión
agresivo, que aprovecha la redundancia geométrica que se suele encontrar en
grandes modelos 3D para comprimir los datos de forma que quepan, en un formato
totalmente renderizable, en la memoria de la GPU. El método está diseñado para
representaciones voxelizadas de escenas 3D, que son ampliamente utilizadas para
diversos cálculos como la aceleración las consultas de visibilidad en la GPU o el
trazado de sombras. La compresión se logra fusionando subárboles idénticos a través
de una transformación de similitud, y aprovechando la distribución no homogénea de
referencias a nodos compartidos para almacenar punteros a los nodos hijo, utilizando
una codificación de bits variable. La capacidad y el rendimiento de todos los métodos
se evalúan utilizando diversos casos de uso del mundo real de diversos ámbitos y
sectores, incluidos el patrimonio cultural, la ingeniería y los videojuegos.[Abstract] This thesis introduces scalable techniques that advance the state-of-the-art in massive model creation and exploration. Concerning model creation, we present methods for improving reality-based scene acquisition and processing, introducing an efficient
implementation of scalable out-of-core point clouds and a data-fusion approach for
creating detailed colored models from cluttered scene acquisitions. The core of this
thesis concerns enabling technology for the exploration of general large datasets.
Two novel solutions are introduced. The first is an adaptive out-of-core technique
exploiting the GPU rasterization pipeline and hardware occlusion queries in order
to create coherent batches of work for localized shader-based ray tracing kernels,
opening the door to out-of-core ray tracing with shadowing and global illumination.
The second is an aggressive compression method that exploits redundancy in large
models to compress data so that it fits, in fully renderable format, in GPU memory.
The method is targeted to voxelized representations of 3D scenes, which are widely
used to accelerate visibility queries on the GPU. Compression is achieved by merging
subtrees that are identical through a similarity transform and by exploiting the skewed
distribution of references to shared nodes to store child pointers using a variable bitrate
encoding The capability and performance of all methods are evaluated on many
very massive real-world scenes from several domains, including cultural heritage,
engineering, and gaming
Vertex classification for non-uniform geometry reduction.
Complex models created from isosurface extraction or CAD and highly accurate 3D models produced from high-resolution scanners are useful, for example, for medical simulation, Virtual Reality and entertainment. Often models in general require some sort of manual editing before they can be incorporated in a walkthrough, simulation, computer game or movie. The visualization challenges of a 3D editing tool may be regarded as similar to that of those of other applications that include an element of visualization such as Virtual Reality. However the rendering interaction requirements of each of these applications varies according to their purpose. For rendering photo-realistic images in movies computer farms can render uninterrupted for weeks, a 3D editing tool requires fast access to a model's fine data. In Virtual Reality rendering acceleration techniques such as level of detail can temporarily render parts of a scene with alternative lower complexity versions in order to meet a frame rate tolerable for the user. These alternative versions can be dynamic increments of complexity or static models that were uniformly simplified across the model by minimizing some cost function. Scanners typically have a fixed sampling rate for the entire model being scanned, and therefore may generate large amounts of data in areas not of much interest or that contribute little to the application at hand. It is therefore desirable to simplify such models non-uniformly. Features such as very high curvature areas or borders can be detected automatically and simplified differently to other areas without any interaction or visualization. However a problem arises when one wishes to manually select features of interest in the original model to preserve and create stand alone, non-uniformly reduced versions of large models, for example for medical simulation. To inspect and view such models the memory requirements of LoD representations can be prohibitive and prevent storage of a model in main memory. Furthermore, although asynchronous rendering of a base simplified model ensures a frame rate tolerable to the user whilst detail is paged, no guarantees can be made that what the user is selecting is at the original resolution of the model or of an appropriate LoD owing to disk lag or the complexity of a particular view selected by the user. This thesis presents an interactive method in the con text of a 3D editing application for feature selection from any model that fits in main memory. We present a new compression/decompression of triangle normals and colour technique which does not require dedicated hardware that allows for 87.4% memory reduction and allows larger models to fit in main memory with at most 1.3/2.5 degrees of error on triangle normals and to be viewed interactively. To address scale and available hardware resources, we reference a hierarchy of volumes of different sizes. The distances of the volumes at each level of the hierarchy to the intersection point of the line of sight with the model are calculated and these distances sorted. At startup an appropriate level of the tree is automatically chosen by separating the time required for rendering from that required for sorting and constraining the latter according to the resources available. A clustered navigation skin and depth buffer strategy allows for the interactive visualisation of models of any size, ensuring that triangles from the closest volumes are rendered over the navigation skin even when the clustered skin may be closer to the viewer than the original model. We show results with scanned models, CAD, textured models and an isosurface. This thesis addresses numerical issues arising from the optimisation of cost functions in LoD algorithms and presents a semi-automatic solution for selection of the threshold on the condition number of the matrix to be inverted for optimal placement of the new vertex created by an edge collapse. We show that the units in which a model is expressed may inadvertently affect the condition of these matrices, hence affecting the evaluation of different LoD methods with different solvers. We use the same solver with an automatically calibrated threshold to evaluate different uniform geometry reduction techniques. We then present a framework for non-uniform reduction of regular scanned models that can be used in conjunction with a variety of LoD algorithms. The benefits of non-uniform reduction are presented in the context of an animation system. (Abstract shortened by UMI.)
Scalable Exploration of Complex Objects and Environments Beyond Plain Visual Replication
Digital multimedia content and presentation means are rapidly increasing their sophistication and are now capable of describing detailed representations of the physical world. 3D exploration experiences allow people to appreciate, understand and interact with intrinsically virtual objects.
Communicating information on objects requires the ability to explore them under different angles, as well as to mix highly photorealistic or illustrative presentations of the object themselves with additional data that provides additional insights on these objects, typically represented in the form of annotations. Effectively providing these capabilities requires the solution of important problems in visualization and user interaction.
In this thesis, I studied these problems in the cultural heritage-computing-domain, focusing on the very common and important special case of mostly planar, but visually, geometrically, and semantically rich objects. These could be generally roughly flat objects with a standard frontal viewing direction (e.g., paintings, inscriptions, bas-reliefs), as well as visualizations of fully 3D objects from a particular point of views (e.g., canonical views of buildings or statues). Selecting a precise application domain and a specific presentation mode allowed me to concentrate on the well defined use-case of the exploration of annotated relightable stratigraphic models (in particular, for local and remote museum presentation).
My main results and contributions to the state of the art have been a novel technique for interactively controlling visualization lenses while automatically maintaining good focus-and-context parameters, a novel approach for avoiding clutter in an annotated model and for guiding users towards interesting areas, and a method for structuring audio-visual object annotations into a graph and for using that graph to improve guidance and support storytelling and automated tours.
We demonstrated the effectiveness and potential of our techniques by performing interactive exploration sessions on various screen sizes and types ranging from desktop devices to large-screen displays for a walk-up-and-use museum installation.
KEYWORDS - Computer Graphics, Human-Computer Interaction, Interactive Lenses, Focus-and-Context, Annotated Models, Cultural Heritage Computing