Procedural function-based modelling of volumetric microstructures

We propose a new approach to modelling heterogeneous objects containing internal volumetric structures with size of details orders of magnitude smaller than the overall size of the object. The proposed function-based procedural representation provides compact, precise, and arbitrarily parameterised models of coherent microstructures, which can undergo blending, deformations, and other geometric operations, and can be directly rendered and fabricated without generating any auxiliary representations (such as polygonal meshes and voxel arrays). In particular, modelling of regular lattices and cellular microstructures as well as irregular porous media is discussed and illustrated. We also present a method to estimate parameters of the given model by fitting it to microstructure data obtained with magnetic resonance imaging and other measurements of natural and artificial objects. Examples of rendering and digital fabrication of microstructure models are presented

Management and display of four-dimensional environmental data sets using McIDAS

Over the past four years, great strides have been made in the areas of data management and display of 4-D meteorological data sets. A survey was conducted of available and planned 4-D meteorological data sources. The data types were evaluated for their impact on the data management and display system. The requirements were analyzed for data base management generated by the 4-D data display system. The suitability of the existing data base management procedures and file structure were evaluated in light of the new requirements. Where needed, new data base management tools and file procedures were designed and implemented. The quality of the basic 4-D data sets was assured. The interpolation and extrapolation techniques of the 4-D data were investigated. The 4-D data from various sources were combined to make a uniform and consistent data set for display purposes. Data display software was designed to create abstract line graphic 3-D displays. Realistic shaded 3-D displays were created. Animation routines for these displays were developed in order to produce a dynamic 4-D presentation. A prototype dynamic color stereo workstation was implemented. A computer functional design specification was produced based on interactive studies and user feedback

CAVASS: A Computer-Assisted Visualization and Analysis Software System

The Medical Image Processing Group at the University of Pennsylvania has been developing (and distributing with source code) medical image analysis and visualization software systems for a long period of time. Our most recent system, 3DVIEWNIX, was first released in 1993. Since that time, a number of significant advancements have taken place with regard to computer platforms and operating systems, networking capability, the rise of parallel processing standards, and the development of open-source toolkits. The development of CAVASS by our group is the next generation of 3DVIEWNIX. CAVASS will be freely available and open source, and it is integrated with toolkits such as Insight Toolkit and Visualization Toolkit. CAVASS runs on Windows, Unix, Linux, and Mac but shares a single code base. Rather than requiring expensive multiprocessor systems, it seamlessly provides for parallel processing via inexpensive clusters of work stations for more time-consuming algorithms. Most importantly, CAVASS is directed at the visualization, processing, and analysis of 3-dimensional and higher-dimensional medical imagery, so support for digital imaging and communication in medicine data and the efficient implementation of algorithms is given paramount importance

Animating ultra-complex voxel scenes through shell deformation

version draft du mémoireInternational audienceVoxel representations have many advantages, such as ordered traversal during rendering and trivial very decent LOD through MIPmap. Special effect companies such Digital Domain or Rhythm&Hues now ex- tensively use voxels engines, for semi-transparent objects such as clouds, avalanches, tornado or explosions, but also for complex solid objects. Several gaming companies are also looking into voxel engines to deal with ever more complex scenes but the main problem when dealing with voxel representations is the amount of data that has to be manipulated. This amount usually prevents animating in real time. To solve these is- sues, ARTIS team developed the Gigavoxels framework: a very powerful voxel engine based on GPU ray-casting, with advanced memory man- agement, so that very complex scenes can be rendered in real-time. The purpose of the TER was to develop a solution for animating voxel objects in real-time, implement it and eventually integrate it to the Gigavoxels framework

Emerging Technologies in Architectural Visualization: Implementation Strategies for Practice

Representation has always been a critical component in architectural practice and representational techniques have been evolving over time. The relatively recent advent of the digital media is revolutionizing architectural representation. Digital representation techniques are proving to be a more effective means of communicating the design to the client and the collaborative project team. The techniques are advancing so rapidly that it is becoming increasingly difficult to keep in pace with the digital acceleration and utilize these representation techniques in architectural practice. There is a wide difference between what is possible using digital architectural visualization and what is implemented in practice. The research explores the extent of utilization of these digital representation techniques and the challenges they pose in practical implementation. Employing a logical approach to selectively implement this digital procedural change in representation would help in realizing the strategic benefits of these rapidly progressing techniques

Compressive Sensing for Dynamic XRF Scanning

X-Ray Fluorescence (XRF) scanning is a widespread technique of high importance and impact since it provides chemical composition maps crucial for several scientific investigations. There are continuous requirements for larger, faster and highly resolved acquisitions in order to study complex structures. Among the scientific applications that benefit from it, some of them, such as wide scale brain imaging, are prohibitively difficult due to time constraints. However, typically the overall XRF imaging performance is improving through technological progress on XRF detectors and X-ray sources. This paper suggests an additional approach where XRF scanning is performed in a sparse way by skipping specific points or by varying dynamically acquisition time or other scan settings in a conditional manner. This paves the way for Compressive Sensing in XRF scans where data are acquired in a reduced manner allowing for challenging experiments, currently not feasible with the traditional scanning strategies. A series of different compressive sensing strategies for dynamic scans are presented here. A proof of principle experiment was performed at the TwinMic beamline of Elettra synchrotron. The outcome demonstrates the potential of Compressive Sensing for dynamic scans, suggesting its use in challenging scientific experiments while proposing a technical solution for beamline acquisition software.Comment: 16 pages, 7 figures, 1 tabl

The Rise and Fall of The Thin Concrete Shell

Concrete was a popular material choice that stretched the imagination of building designers over past decades. This material that imbued notions of plasticity and flow, sets innovative ideals soaring with hope in the postwar landscape, seen as the material of the future. This paper seeks to perspectivise the phenomenonal rise of the material in the application of shell construction using key case studies of built examples from Nervi, Candela and Isler. It also aims to chart the subsequent demise of its application in thin shell design. By understanding the reasons to what led to its demise, designers will be able to erect concrete shells more sustainably, by modifications to the design process, construction stages and thoughtful consideration to formwork implementation to meet the demands of the 21st century and beyond. This paper discusses the possibilities of concrete as a material of choice and by asking the question to what constituted its popularity and what led to its demise in this age of new technological advances, construction processes and environmental concerns. This paper will present a cultural perspective of the material and the important relationship between concrete with its formwork to bring about a new renaissance to the reappearance of such structures in our built environment once again