Caterina Rizzi

3D virtual apparel design for industrial applications

The integration of physics-based models within CAD systems for garment design leads to highly accurate cloth shape results for virtual prototyping and quality evaluation tasks. To this aim, we present a physics-based system for virtual cloth design and simulation expressly conceived for design purposes. This environment should allow the designer to validate her/his style and design option through the analysis of garment virtual prototypes and simulation results in order to reduce the number and role of physical prototypes. Garment shapes are accurately predicted by including material properties and external interactions through a particle-based cloth model embedded in constrained Newtonian dynamics with collision management, extended to complex-shaped assembled and finished garments. Our model is incorporated within a 3D graphical environment, and includes operators monitoring the whole design process of apparel, e.g. panel sewing, button/dart insertion, multi-layered fabric composition, garment finishings, etc. Applications and case studies are considered, with analysis of CAD modelling phases and simulation results concerning several male and female garments.

A new design paradigm for the development of custom-fit soft sockets for lower limb prostheses

This paper presents a new 3D design paradigm for the development of specific custom-fit products, such as the soft socket of prostheses for lower limb amputees. It is centered on the digital model of the human body and, contrarily to the traditional process almost manually based, it considers the integration of methods and tools coming from different research and application fields: Reverse Engineering, Medical Imaging, Virtual Prototyping, Physics-based Simulation, and Rapid Prototyping. The paper describes the techniques adopted to acquire and create the digital model of the residual limb, the procedure to generate the socket model, the strategy developed for the functional simulation of the socket-stump interaction and, finally, the realization of the physical prototype. Each design step is described with the related problems and the obtained results. Both trans-tibial and trans-femoral amputees have been considered; however, for now the complete process has been validated for trans-tibial prostheses. Major outcomes of the proposed approach stand in a better quality of the final product, in a shorter involvement of the amputee implying a lower psychological impact, in a limited use of physical prototypes, and in a shorter development time. Moreover, the resulting paradigm answers to the Collaborative Engineering guidelines by optimizing the interaction between different domains and enhancing their contributions in a homogeneous development framework.

Structural optimization strategies to design green products

This paper addresses the need for a structured approach to environmental assessment and improvement. We propose a computer-aided methodology, named Eco-OptiCAD, based on the integration of Structural Optimization and Life Cycle Assessment (LCA) tools. Eco-OptiCAD supports the designer during product development, highlighting when and where the core of the environmental impact lies. Furthermore, it provides effective tools to address such impacts, improving the original product, while ensuring structural and functional requirements. It foresees the synergic use of (1) virtual prototyping tools, such as 3D CAD, Finite Element Analysis (FEA) and Structural optimization, (2) function modeling methodology and (3) Life Cycle Assessment (LCA) tools. The kernel of the methodology is constituted by a set of optimization strategies and a module, named Life Cycle Mapping (LCM). In particular, we have conceived ten optimization strategies converting environmental objectives and constraints into structural and geometrical parameters. They enable the designer to generate alternative green scenarios according to the triad shape-material-production. The LCM tool has been specifically developed to easily trace the growth of environmental impacts throughout the products life cycle and allow the user to focus his effort on the most relevant aspects. Thanks to the integration of the structural optimizer with an LCA map, the designer becomes aware of the consequences that each change in the geometry, the material or the manufacturing process will produce on the environmental impact of the product throughout its life cycle. With a complete view of the product life cycle, the designer can improve a single phase, while retaining a global perspective; thus avoiding the possibility of gaining a local green improvement at the cost of a global increase in environmental impacts. An exemplary case study is presented to detail each step of the design methodology and shows its potential. Eco-OptiCAD represents a first step toward a fully integrated system for eco-design assessment and improvement, with the potential of working side by side with common design tools, in providing a constant environmental feedback.

PLM paradigm: How to lead BPR within the Product Development field

The design and implementation of a PLM solution in a cross-company environment is a complex and labour intensive operation, which is often coupled with a Business Process Re-engineering (BPR) project to better deploy technologies as well as methodologies and to target the system implementation on the real company needs. Enterprise Modelling (EM) languages are typically used to collect and share process knowledge among the BPR participants. Plenty of techniques are actually available at this scope and it is not always easy to understand how to select and use them in the different steps of re-engineering. The main purpose of this paper is to perform a qualitative analysis of three well known EM languages (IDEF, UML and ARIS) and to propose a new methodology, based on their integrated use, supporting BPR efforts in the Product Development domain.

Innovation in product design: from CAD to virtual prototyping

Innovation in Product Design gives an overview of the research fields and achievements in the development of methods and tools for product design and innovation. It presents contributions from experts in many different fields covering a variety of research topics related to product development and innovation. Product lifecycle management, knowledge management, product customization, topological optimization, product virtualization, systematic innovation, virtual humans, design and engineering, and rapid prototyping are the key research areas described in the book. It also details successful case studies developed with industrial companies. Innovation in Product Design is written for academic researchers, graduate students and professionals in product development disciplines who are interested in understanding how novel methodologies and technologies can make the product development process more efficient.

A CAD-oriented cloth simulation system with stable and efficient ODE solution

Cloth modelling is a research field of increasing interest both for computer animation and computer-aided design purposes. Aiming at being closer to cloth manufacturers needs, this work proposes an integration of a particle-based modelling approach within a CAD oriented system for real design of apparel and complex-shaped cloth. The particle-based model, originally defined on single textile layers, is extended to take into account the physical effects of seams and darts, construction constraints, layered parts, and other manufacturing processes that contribute to the final shape of the garments. Starting from an initial 3D configuration of the particle grid consistent with mannequin and support geometries, the physical simulation process is then computed, based on constrained Newtonian dynamics laws. Stable and efficient algorithms for the time discretization of the Newtonian ODE problem are proposed, based on implicit and semi-implicit BDF(2) or hybrid Euler-BDF(2) techniques. As applications, several test models are considered, simulated on rigid supports or mannequins, for both numerical comparisons and global shape analysis, from simple cloth geometries up to complex-shaped models for real apparel manufacturing.

Racing car design using knowledge aided engineering

The evolution of computer aided design (CAD) systems and related technologies has promoted the development of software for the automatic configuration of mechanical systems. This occurred with the introduction of knowledge aided engineering (KAE) systems that enable computers to support the designer during the decision-making process. This paper presents a knowledge-based application that allows the designer to automatically compute and evaluate mass properties of racing cars. The system is constituted by two main components: the computing core, which determines the car model, and the graphic user interface, because of which the system may be used also by nonprogrammers. The computing core creates the model of the car based on a tree structure, which contains all car subsystems (e.g., suspension and chassis). Different part–subpart relationships define the tree model and link an object (e.g., suspension) to its components (e.g., wishbones and wheel). The definition of independent parameters (including design variables) and relationships definition allows the model to configure itself by evaluating all properties related to dimension, position, mass, etc. The graphic user interface allows the end user to interact with the car model by editing independent design parameters. It visualizes the main outputs of the model, which consist in numeric data (mass, center of mass of both the car and its subsystems) and graphic elements (car and subsystems 3D representation).

Digital Human Models and Virtual Ergonomics to Improve Maintainability

Maintenance is one of the key drivers for future company success, due to the fact that these kinds of operations are strictly related to human labor cost, an expensive factor for western states. Furthermore, in the last decades, norms and laws on safety and ergonomics of the work place have taken importance among industrialized countries. Design for Maintenance is a design methodology that since early stages of product life cycle outlines needs and necessities of maintainers, in order to reduces time and cost; decreasing the complexity and the difficulties of these procedures and achieving a higher standard of workers’ health. In order to reach this goal, Digital Human Models (DHM) have been used to simulate assembly and maintenance processes. Virtual ergonomic analysis performed with a human model allows evaluating visibility, reachability and postures, stress and fatigue. The lack of methods supporting virtual ergonomics simulation has been addressed by proposing a systematic approach based on a step-by...

A digital patient for computer-aided prosthesis design

This article concerns the design of lower limb prosthesis, both below and above knee. It describes a new computer-based design framework and a digital model of the patient around which the prosthesis is designed and tested in a completely virtual environment. The virtual model of the patient is the backbone of the whole system, and it is based on a biomechanical general-purpose model customized with the patients characteristics (e.g. anthropometric measures). The software platform adopts computer-aided and knowledge-guided approaches with the goal of replacing the current development process, mainly hand made, with a virtual one. It provides the prosthetics with a set of tools to design, configure and test the prosthesis and comprehends two main environments: the prosthesis modelling laboratory and the virtual testing laboratory. The first permits the three-dimensional model of the prosthesis to be configured and generated, while the second allows the prosthetics to virtually set up the artificial leg and simulate the patients postures and movements, validating its functionality and configuration. General architecture and modelling/simulation tools for the platform are described as well as main aspects and results of the experimentation.

ClothAssembler: a CAD Module for Feature-based Garment Pattern Assembly

AbstractThis work presents a CAD prototype, named ClothAssembler, targeted at complex-shaped apparel design for real manufacturing. The intent is to fill a gap in the current CAD technology for garment design as it is mainly conceived for 2D/3D geometric modelling of cloth shapes, but generally does not provide high level operators that allow interactive and easy design of aesthetic/functional features that characterize the garment pieces, and relations/connections between parts. Though still an academic prototype, ClothAssembler allows to define/choose in an interactive way all the necessary geometric and functional information for the design and finishing of 2D pieces, such as insertion of textile layers, reinforcement lines, pockets, cut lines and pleats, as well as topological information about how pieces are pair-wise connected and assembled, by definition of seams, darts, zips, constraints such as buttons and hooks, etc. A taxonomy and parametrization of cloth tailoring features is discussed, and sy...