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