Table Of ContentSpringer
Berlin
Heidelberg
New York
Barcelona
Budapest
Hong Kong
London
Milan
Paris
Santa Clara
Singapore
Tokyo
D. Roller P. Brunet (Eds.)
CAD
Systems
Development
Tools and Methods
With 159 Figures and 6 Tables
Springer
Dieter Roller
Universitat Stuttgart
Institut fur Informatik
Breitwiesenstrasse 20-22
D-70565 Stuttgart
Germany
Pere Brunet
Universitat Politecnica de Catalunya
Dep. de Llenguatges i Sistemes Informatics
Av. Diagonal 647, 8a
E-08028 Barcelona
Spain
Cataloging-in-Publication Data applied for
Die Deutsche Bibliothek - CIP-Einheitsaufnahme
CAD systems development: tools and methods I D. Roller; P.
Brunet (ed.). - Berlin; Heidelberg; New York; Barcelona;
Budapest ; Hong Kong; London ; Milan; Paris ; Santa Clara;
Singapore; Tokyo: Springer, 1997
ISBN-13:978-3-642-64523-5 e-ISBN-13:978-3-642-60718-9
DOl: 10.10071978-3-642-60718-9
NE: Roller. Dieter [Hrsg.]
ISBN-13:978-3-642-64523-5 Springer-Verlag Berlin Heidelberg New York
This work is subject to copyright. All rights are reserved, whether the whole or part of the material is
concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broad
casting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of
this publication or parts thereof is permitted only under the provisions of the German Copyright
Law of September 9, 1965, in its current version, and permission for use must always be obtained
from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law.
© Springer-Verlag Berlin Heidelberg 1997
Softcover reprint of the hardcover 1st edition 1997
The use of general descriptive names, registered names, trademarks, etc. in this publication does not
imply, even in the absence of a specific statement, that such names are exempt from the relevant pro
tective laws and regulations and therefore free for general use.
Typesetting: Camera-ready copy by authors
Cover design: design 6-production GmbH, Heidelberg
SPIN 10529763 33/3142 - 543210 - Printed on acid-free paper
Preface
This book is based on lectures presented at the first seminar on CAD
Tools for Products at the SchloB Dagstuhl International Conference and
Research Center for Computer Science. Experts from academia and
industry were invited, and reported on selected and relevant topics in
the area. The resulting papers, published in this volume, give a state-of
the-art survey of the relevant problems and issues.
This volume is divided into six chapters, focusing on the most
significant aspects in future CAD architectures, product modeling,
feature based design, design of complex surfaces, parametric and
constraint modeling, and algorithmic aspects.
The first chapter includes new advances in future CAD architectures,
with contributions from Abeln, Dankwort, Hoffmann, Mink & Roller,
and Krause, Jansen & Kiesewetter. In his section, Abeln presents the
CAD-Reference Model join project, supported by the German minister
for research. Proposals for an improved, feasible configuration for CAD
systems are being generated. In the second section, Dankwort presents
a common long-term strategy for the CAD-CAM R&D departments of
the German automotive industry. It has lead to the concept of a new
CAx system architecture which is described. Hoffmann presents an
overview of the EREP project, offering a neutral CAD product represen
tation able for exchanging design data that incorporates features and
constraints. The fourth section is devoted to electrical engineering CAD
systems. Mink and Roller make proposals for the development of the
architecture of the new generation electrical engineering CAD systems,
requirements for ECAD and differences with respect to mechanical CAD
systems being emphasized. Eventually, Krause, Jansen and Kiesewetter
propose a multimedia based working environment, allowing the inte
gration of commercial CAD systems with distributed product data
management into a system environment for distributed cooperative
work.
vi CAD Systems Development -Tools and Methods
Chapter two, on product modeling, includes three sections on product
modeling tools. Jared discusses the main problems and trends associa
ted with Design for Manufacture and Design for Assembly, and how to
provide product model support for them. Mantyla's section deals with
extracting reusable product data, presenting the process planning
system MCOES++. MCOES facilitates the reuse of production data at
various time scales on the basis of feature-oriented product and pro
duction process models. Finally, Rix and Kress discuss the integration of
existing technologies in CAD modeling, design, analysis, simulation,
networked cooperation and virtual reality, in order to use virtual proto
types to support the integrated product development process.
The third chapter presents new advances in feature-based design.
Dealing with feature validation and conversion, Jan de Kraker, Dohmen
and Bronsvoort present a new approach supporting multiple feature
views of the product. A central cellular model links the feature models
from the different views and performs feature conversion when needed.
De Martino, Falcidieno and Petta present the feature recognition
subsystem in an integrated system using design-by-features and feature
recognition; it is based on a feature classification strategy. On the other
hand, extending feature concepts to free form surface models is the goal
of Hagen and Hahmann's section: they present feature stability as an
analysis tool for complex surfaces, by detecting regions that are likely to
bend or deform. Finally, a new representation scheme for feature based
parametric design is proposed in Brunetti and Vieira's section: a para
metric feature representation is introduced including geometry, topolo
gy, parameters and constraints, such that it can be used in feature
based parametric design integrating design by features and parametric
design.
Chapter four, on complex surface design, includes three sections on
novel techniques for surfaces. The transfinite B-Spline interpolation
problem with derivatives is discussed by Gschwind and Hagen. They
propose an scheme for the transfinite interpolation of a grid of B-Spline
curves, G 1 or G2 continuity being required. The problem is transformed
into an equivalent point interpolation problem. Heinz's section describes
an application of variational design algorithms to surface reconstruction
with variable offsets. After this, Sapidis presents an algorithm for
variable-order surface reconstruction through region growing, trans
forming a dense point cloud from range image sensors into a CAD
polynomial surface model. Finally, the conversion of Dupin Cyclides into
Principal Patches is studied by Zhou and Roller: the relationship bet
ween the two rational parametric representations of cyclides is studied
and conversion algorithms are proposed.
Preface vii
Chapter five deals with parametric modeling and includes three
sections. Pratt discusses several considerations which have arisen in the
enhancement of STEP in order to support parametric and constrained
geometry and feature-based representations. Rosendahl, Berling and
Du propose a new kind of segments that encapsulate objects with pos
sible geometric and numerical relationships among each other. Rela
tionships are possible also between objects belonging to different
segments. Eventually, a hybrid constraint solver using exact and itera
tive geometric constructions is presented by Hsu and Briiderlin: they
propose a hybrid constraint solver on a graph, based on degrees of
freedom and valencies which combines a direct geometric approach with
an iterative algorithm based on the multivariate secant method.
Finally, several algorithmic tools for novel CAD architectures are
presented in chapter six. Joan-Arinyo, Perez-Vidal and Gargallo intro
duce an adaptive algorithm to compute the medial axis transform of 2D
polygonal domains. The algorithm is based on the refinement of a coarse
medial axis transform by an adaptive subdivision of the polygonal
domain. Garcia-Alonso and Matey's section is dedicated to tools for
mechanical analysis and simulation: two network-based facilities for
CAD-CAE of multibody systems are described, namely a computer
supported cooperative work environment and a distributed simulation
prototype. The section from Klein proposes an improved divide-and
conquer algorithm for the construction of the constrained Delaunay
triangulation of a polygonal domain. After this, tools for handling very
complex environments and assemblies are presented in the two final
sections: Navazo and Vila propose an algorithm to compute a weak
visibility graph for a large data set based on its discretization by means
of a regular uniform grid, being useful as a preprocess step in walk
through navigations. On the other hand, Ayala, Brunet, Joan-Arinyo
and N avazo discuss several simplification algorithms for the automatic
generation of multiresolution models of polyhedral solids, presenting
and discussing octree-based simplification algorithms.
Many people have contributed to the success of the seminar and to
the preparation of this book. particularly, we would like to thank the
authors who submitted papers and prepared them for this edition, and
we also want to thank the reviewers for their efforts in setting the
standard for the quality of contributions in this volume.
Stuttgart / Barcelona Dieter Roller
Autumn 1996 Pere Brunet
Contents
Chapter 1
Future CAD Architectures 1
The "CAD-Reference-Model": An Architectural Approach to
Future CAD-Systems ................................................................... 3
CAx Systems Architecture ofthe Future ........................................ 20
EREP Project Overview .................................................................. 32
New ECAD System Technology ..................................................... .41
Cooperative Product Development with heterogeneous CAD
systems via EDM and Broadband Communication
Technique .................................................................................... 55
Chapter 2
Product Data and Development Process 71
Product Modelling for Design for Manufacture and Design
for Assembly ................................................................................ 73
Extracting Reusable Product Data ................................................. 89
Virtual Prototyping -An Open System Environment to
Support the Integrated Product Development Process ............ 106
Chapter 3
Feature Technology 119
Feature validation and conversion ............................................... 121
Classification of generic shape features for the recognition of
specific feature instances .......................................................... 143
Stability Features for Free Form Surfaces ................................... 157
Representation Scheme for Feature-based Parametric Design .... 165
x CAD Systems Development -Tools and Methods
Chapter 4
Complex Surface Design 181
Transfinite B-spline Interpolation with Derivates ........................ 183
Surface Reconstruction and Variable Offset .................................. 199
Variable-Order Surface Reconstruction Through Region
Growing. ........................................................................................ 207
On the Conversion of Dupin Cyclide into Principal Patches ......... 219
Chapter 5
Parametric Modelling 235
Extension of STEP for the Representation of Parametric and
Variational Models ....................................................................... 237
A Generalised Segment Concept ..................................................... 251
A Hybrid Constraint Solver Using Exact and Iterative
Geometric Constructions ............................................................. 265
Chapter 6
Algorithmic Aspects 281
An Adaptive Algorithm to Compute the Medial Axis
Transform of 2-D Polygonal Domains ......................................... 283
Tools for Mechanical Analysis and Simulation .............................. 299
Construction Of The Constrained Delaunay Triangulation Of
A Polygonal Domain ..................................................................... 313
Multiresolution Approximation of Polyhedral Solids ..................... 327
Handling Very Complex Environments Using a Discrete
Visibility Graph ............................................................................ 344
Index 357
Chapter 1
Future CAD Architectures
Overview
The "CAD-Reference-Model": An Architectural Approach to
Future CAD-Systems ................................................................... 3
CAx Systems Architecture of the Future ........................................ 20
EREP Project Overview .................................................................. 32
New ECAD System Technology ..................................................... .41
Cooperative Product Development with heterogeneous CAD
systems via EDM and Broadband Communication
Technique .................................................................................... 55
The "CAD-Reference-Moder'
An Architectural Approach to
Future CAD -Systems
Olaf Abeln-
This section describes a joint project being carried out by eight
research centers in Germany, together with industry and CAD vendor
participants. The objective is the development of a new-generation
CAD system which builds on past experience but meets the require
ments of users much more satisfactorily than is the case with existing
systems. The paper concentrates on the "CAD-Reference-Model"
which has been created during the initial stage of the project.
Introduction
The German industry has been using CAD-systems for more than
twenty years. Most of the companies have installed some kind of
CAD-workstation and software-packages for special tasks of the
design process. But in the course of fulfilment of a business
commission the penetration of using CAD-systems is lower than 20%.
The rather complicated handling, the unmoveable structure of the
systems, the overload number and variety of commands of the CAD
systems, the absence of any integration tools and the lack of a
common product data model are the main reasons for this
discrepancy and for the missing acceptance of the users. The future
-The Computer Science Research Center at the
University of Karlsruhe, Karlsruhe FRG
D. Roller et al. (eds.), CAD Systems Development
© Springer-Verlag Berlin Heidelberg 1997
