226,362 research outputs found
Geometric Surface Processing and Virtual Modeling
In this work we focus on two main topics "Geometric Surface Processing" and "Virtual Modeling". The inspiration and coordination for most of the research work contained in the thesis has been driven by the project New Interactive and Innovative Technologies for CAD (NIIT4CAD), funded by the European Eurostars Programme. NIIT4CAD has the ambitious aim of overcoming the limitations of the traditional approach to surface modeling of current 3D CAD systems by introducing new methodologies and technologies based on subdivision surfaces
in a new virtual modeling framework. These innovations will allow designers and engineers to transform quickly and intuitively an idea of shape in a high-quality geometrical model suited for engineering and manufacturing purposes.
One of the objective of the thesis is indeed the reconstruction and modeling of surfaces, representing arbitrary topology objects, starting from 3D irregular curve networks acquired through an ad-hoc smart-pen device.
The thesis is organized in two main parts: "Geometric Surface Processing" and "Virtual Modeling". During the development of the geometric pipeline in our Virtual Modeling system, we faced many challenges that captured our interest and opened new areas of research and experimentation.
In the first part, we present these theories and some applications to Geometric Surface Processing.
This allowed us to better formalize and give a broader understanding on some of the techniques used in our latest advancements on virtual modeling and surface reconstruction.
The research on both topics led to important results that have been published and presented in articles and conferences of international relevance
Data-Driven Shape Analysis and Processing
Data-driven methods play an increasingly important role in discovering
geometric, structural, and semantic relationships between 3D shapes in
collections, and applying this analysis to support intelligent modeling,
editing, and visualization of geometric data. In contrast to traditional
approaches, a key feature of data-driven approaches is that they aggregate
information from a collection of shapes to improve the analysis and processing
of individual shapes. In addition, they are able to learn models that reason
about properties and relationships of shapes without relying on hard-coded
rules or explicitly programmed instructions. We provide an overview of the main
concepts and components of these techniques, and discuss their application to
shape classification, segmentation, matching, reconstruction, modeling and
exploration, as well as scene analysis and synthesis, through reviewing the
literature and relating the existing works with both qualitative and numerical
comparisons. We conclude our report with ideas that can inspire future research
in data-driven shape analysis and processing.Comment: 10 pages, 19 figure
GraXML - Modular Geometric Modeler
Many entities managed by HEP Software Frameworks represent spatial
(3-dimensional) real objects. Effective definition, manipulation and
visualization of such objects is an indispensable functionality.
GraXML is a modular Geometric Modeling toolkit capable of processing
geometric data of various kinds (detector geometry, event geometry) from
different sources and delivering them in ways suitable for further use.
Geometric data are first modeled in one of the Generic Models. Those Models are
then used to populate powerful Geometric Model based on the Java3D technology.
While Java3D has been originally created just to provide visualization of 3D
objects, its light weight and high functionality allow an effective reuse as a
general geometric component. This is possible also thanks to a large overlap
between graphical and general geometric functionality and modular design of
Java3D itself. Its graphical functionalities also allow a natural visualization
of all manipulated elements.
All these techniques have been developed primarily (or only) for the Java
environment. It is, however, possible to interface them transparently to
Frameworks built in other languages, like for example C++.
The GraXML toolkit has been tested with data from several sources, as for
example ATLAS and ALICE detector description and ATLAS event data. Prototypes
for other sources, like Geometry Description Markup Language (GDML) exist too
and interface to any other source is easy to add.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003. PSN THJT00
Computing a Compact Spline Representation of the Medial Axis Transform of a 2D Shape
We present a full pipeline for computing the medial axis transform of an
arbitrary 2D shape. The instability of the medial axis transform is overcome by
a pruning algorithm guided by a user-defined Hausdorff distance threshold. The
stable medial axis transform is then approximated by spline curves in 3D to
produce a smooth and compact representation. These spline curves are computed
by minimizing the approximation error between the input shape and the shape
represented by the medial axis transform. Our results on various 2D shapes
suggest that our method is practical and effective, and yields faithful and
compact representations of medial axis transforms of 2D shapes.Comment: GMP14 (Geometric Modeling and Processing
Aplikasi Fotogrametri Jarak Dekat Untuk Pemodelan 3d Tugu Muda Semarang
The earth\u27s surface object mapping is largely a three dimensional (3D) object, therefore at this time has began to take a three dimensional map. The basic data used to perform modeling three dimensional objects must have a good level of precision and good geometry precision .In this research, the methods used are the close range photogrametry method for modeling 3D of Tugu Muda using digital cameras non metric. For this phase of the research is divided into stages cameras calibration, object photo shoot, 3D model processing. For the calibration process obtained 80% qualified calibration.For the real photo data capture as many as 96 images and data processing on this research using PhotoModeler Scanner and Summit Evolution a comparative statistical test geometric with Electronic Total Station. The Modeling stage consists of Automated Project, process counts and the creation of models, 3D coordinate transformations, 3D model visualization and 24 geometric points statistical analysis.The final results in this research are 3D model Monument of Tugu Muda Semarang. Testing of the results in 3D modelling processing was done by comparing the 3D model distance referenced to Electronic Total Station measurement. The comparison of the standard deviation value with the Electronic Total Station measurement is 0,101 meters
Mini-Workshop: Analytical and Numerical Methods in Image and Surface Processing
The workshop successfully brought together researchers from mathematical analysis, numerical mathematics, computer graphics and image processing. The focus was on variational methods in image and surface processing such as active contour models, Mumford-Shah type functionals, image and surface denoising based on geometric evolution problems in image and surface fairing, physical modeling of surfaces, the restoration of images and surfaces using higher order variational formulations
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