A New Approach in CAD System for Designing Shoes

The flattening of digitized surfaces is still very important in design of thin walled objects such as the airplane wings, parts of car bodies, textile products, and shoe uppers. Especially in shoe industry, the ability of quick respond to changing market needs is essential for successful competition. To give needed flexibility to a shoe designer, special CAD/CAM systems have been developed. Those systems are based on algorithms for surface reconstruction and surface flattening. In this article a fast algorithm for surface reconstruction and surface flattening is presented. Developable stripes are used to approximate a surface. In this way the surface can be flattened fast and without any distortions

A variational approach for viewpoint-based visibility maximization

We present a variational method for unfolding of the cortex based on a user-chosen point of view as an alternative to more traditional global flattening methods, which incur more distortion around the region of interest. Our approach involves three novel contributions. The first is an energy function and its corresponding gradient flow to measure the average visibility of a region of interest of a surface from a given viewpoint. The second is an additional energy function and flow designed to preserve the 3D topology of the evolving surface. This latter contribution receives significant focus in this thesis as it is crucial to obtain the desired unfolding effect derived from the first energy functional and flow. Without it, the resulting topology changes render the unconstrained evolution uninteresting for the purpose of cortical visualization, exploration, and inspection. The third is a method that dramatically improves the computational speed of the 3D topology-preservation approach by creating a tree structure of the triangulated surface and using a recursion technique.Ph.D.Committee Chair: Allen R. Tannenbaum; Committee Member: Anthony J. Yezzi; Committee Member: Gregory Turk; Committee Member: Joel R. Jackson; Committee Member: Patricio A. Vel

Dizajniranje papirnim trakama - primena na dvostruko zakrivljenim površima

In this paper, we address the challenge of overcoming the problem of developing doubly curved surfaces in product design. Product design uses two kinds of surfaces, developable surfaces and non-developable surfaces, which are also called singly and doubly curved surfaces, respectively. A developable surface has zero Gaussian curvature at all points, while a non-developable surface has non-zero Gaussian curvature at least in some region. Surfaces of many product design object are commonly created as doubly curved shapes to meet requirements of structure and aesthetic. The problem of creating the planar development of 3D surfaces with double curvature in the product design depends on the shape of the surface and the material of the surface cover. Therefore, the method of deriving a pattern is different when external forces are used in order to generate the plane patterns such as paper strips from the case when the plane shape can stretch or deform to fit on the 3D surface. Given a three-dimensional object surface, the first step of the fabrication process is flattening or planar development of this surface into a planar shape so that the manufacturer can not only determine the initial shape of the object but also estimate the strain distribution required to form the shape depending on a material. The paper is analysing and rationalizing doubly curved surface of a given shape by multiple strips of paper glued onto a surface. Results are addressing possibilities of achieving an overall smooth surface and developing a model for the generation of curvature continuous surfaces composed of paper strip surfaces, as well as generating alternative solutions that are in the domain of contemporary product design. The paper illustrates usability and different variations of the proposed design.Ovaj rad se bavi mogućnošću prevazilaženja problema razvijanja u ravan dvostruko zakrivljenih površi u procesu dizajniranja proizvoda. U procesu dizajniranja proizvoda koriste se dve vrste površi, razvojne površi i nerazvojne površi, koje se, takođe, nazivaju jednostruko i dvostruko zakrivljenim površima. Gausova krivina razvojnih površi u svakoj tački jednaka je nuli, dok je kod nerazvojnih površi Gausova krivina ratzličita od nule pa u nekim delovima površi Gausova krivina može da bude pozitivna ili negativna. Površine mnogih dizajn-proizvoda su često osmišljene kao dvostruko zakrivljene površi kako bi zadovoljile strukturne i estetske zahteve. Problem razvijanja u ravan dvostruko zakrivljene trodimenzionalne površi u dizajnu proizvoda zavisi od oblika površine i materijala proizvoda. Stoga, metod pronalaženja načina za razvijanje dvostruko zakrivljene površi u ravan se razlikuje, kada se spoljašnja sila koristi u stvaranju površinskog obrasca kao što je prisutno kod površi (materijala) koje je moguće deformisati, od slučaja razvijanja površi kreiranih od papirnih traka. Posmatrajući površinu trodimenzionalnog objekta, prvi korak u procesu proizvodnje je razvijanje dizajniranog proizvoda u ravan kako bi proizvođač mogao da odredi ne samo inicijalni oblik objekta, već i da raspodeli naprezanje potrebno za formiranje oblika zavisno od materijala. U radu se analizira i racionalizuje dvostruko zakrivljena površ datog oblika korišćenjem papirnih traka zalepljenih na površinu dizajn-proizvoda. Rezultati istražuju mogućnosti postizanja približno glatke površine i razvoja modela za generisanje neprekidne krive površi sastavljene od papirnih traka, kao i kreiranja alternativnih rešenja upotrebljivih u domenu savremenog dizajna proizvoda. Rad ilustruje mogućnost korišćenja različitih varijacija predloženog dizajna

IST Austria Thesis

Fabrication of curved shells plays an important role in modern design, industry, and science. Among their remarkable properties are, for example, aesthetics of organic shapes, ability to evenly distribute loads, or efficient flow separation. They find applications across vast length scales ranging from sky-scraper architecture to microscopic devices. But, at the same time, the design of curved shells and their manufacturing process pose a variety of challenges. In this thesis, they are addressed from several perspectives. In particular, this thesis presents approaches based on the transformation of initially flat sheets into the target curved surfaces. This involves problems of interactive design of shells with nontrivial mechanical constraints, inverse design of complex structural materials, and data-driven modeling of delicate and time-dependent physical properties. At the same time, two newly-developed self-morphing mechanisms targeting flat-to-curved transformation are presented. In architecture, doubly curved surfaces can be realized as cold bent glass panelizations. Originally flat glass panels are bent into frames and remain stressed. This is a cost-efficient fabrication approach compared to hot bending, when glass panels are shaped plastically. However such constructions are prone to breaking during bending, and it is highly nontrivial to navigate the design space, keeping the panels fabricable and aesthetically pleasing at the same time. We introduce an interactive design system for cold bent glass façades, while previously even offline optimization for such scenarios has not been sufficiently developed. Our method is based on a deep learning approach providing quick and high precision estimation of glass panel shape and stress while handling the shape multimodality. Fabrication of smaller objects of scales below 1 m, can also greatly benefit from shaping originally flat sheets. In this respect, we designed new self-morphing shell mechanisms transforming from an initial flat state to a doubly curved state with high precision and detail. Our so-called CurveUps demonstrate the encodement of the geometric information into the shell. Furthermore, we explored the frontiers of programmable materials and showed how temporal information can additionally be encoded into a flat shell. This allows prescribing deformation sequences for doubly curved surfaces and, thus, facilitates self-collision avoidance enabling complex shapes and functionalities otherwise impossible. Both of these methods include inverse design tools keeping the user in the design loop

The development of a hybrid system for designing and pattern making in-set sleeves

This research investigates the relationship between the designer, the pattern maker and the elements that constitute a multiplicity of in-set sleeves. Present sleeve drafting methods represent unpredictable, single-style variations of past methods. They do not vary from the normal non-cohesive practises for any current inset sleeve styles. Current sleeve drafting methods contain only surface explanations for many of the features contained within the sleeve design. Drafting methods are restricted to surface, point-to-point drafting descriptive - they do not convey the actual detailed mechanisms required of the complete scye and sleeve assembly. My perspective suggests that designing and pattern making has scarcely advanced since the beginning of the nineteenth century, or earlier. Therefore, the principal research question is: How might the role of the designer, the tasks of the pattern maker, the many in-set sleeve styles and related fabrics, be combined to create a unique inclusive in-set sleeve design system that is advantageous to the apparel industry? In order to create a unique in-set sleeve design system, this study incorporates a hybrid process derived from a number of design methods. Case studies of a number of sleeve styles and fabrics, representative of a major percentage of the sleeve design range, are developed to confirm the proposition that although each sleeve is a unique entity, they are, contradictory, all one and the same. This is because they are composed of the same limited number of parts and elements. The study details the parts and elements that compose the scye (armhole) and sleeves. These are united with a compilation of engineering drawing methods which are explained and analysed prior to incorporation with additional drawing interpretations. The adoption of engineering drawing methods as a base, with further adaptations, to create a new logical sleeve design system, is seen as a complete break from current trial and error practises to a predictable outcomes-focussed process

Bending-active plates : strategies for the induction of curvature through the means of elastic bending of plate-based structures

Commonly referred to as bending-active, the term has come to describe a wide variety of systems that employ the large defor-mation of their constituent components as a primary shape-forming strategy. It is generally impossible to separate the struc-ture from its geometry, and this is even more true for bending-active systems. Placed at the intersection between geometry, de-sign and engineering, the principle objective of this thesis is to develop an understanding of the structural and architectural po-tential of bending-active systems beyond the established typolo-gies which have been investigated so far. The main focus is set on systems that make use of surface-like elements as principle build-ing blocks, as opposed to previous and existing projects that pre-dominantly employed linear components such as rods and laths. This property places the analysed test cases and developed proto-types within a specific category of bending-active systems known as bending-active plate structures. The first chapters serve as a general introduction to the topic. An overview of relevant recent projects is presented in the introduction, followed by a discussion on the scope of research on bending-active structures. The following chapters lay the theoretical basis in terms of geometry of surfaces and mechanical behaviour of plates. This dual and complementary description serves as the necessary background to understand the limits and potential associated to the deformability of plate elements. The following chapter delves into the first of the two strategies developed as part of this research. Termed form conversion, this approach establishes a one-to-one relationship between the initial base surface and its bending-active discrete counterpart. The chapter proceeds with the presentation of a series of full-scale prototypes that were realised to test the validity of the form con-version approach. Geometrical and mechanical features are dis-cussed in the conclusion of the chapter. The second developed method, named integral approach, is pre-sented in the next section. This approach takes advantage of the inherent deformation properties of explicitly designed material patterns. The description of the method is followed by the presen-tation and discussion of the prototypes chosen to test the integral approach. Finally, the thesis concludes with a critical discussion of the presented approaches and a discussion on potential developments for future research

Design of decorative 3D models: from geodesic ornaments to tangible assemblies

L'obiettivo di questa tesi è sviluppare strumenti utili per creare opere d'arte decorative digitali in 3D. Uno dei processi decorativi più comunemente usati prevede la creazione di pattern decorativi, al fine di abbellire gli oggetti. Questi pattern possono essere dipinti sull'oggetto di base o realizzati con l'applicazione di piccoli elementi decorativi. Tuttavia, la loro realizzazione nei media digitali non è banale. Da un lato, gli utenti esperti possono eseguire manualmente la pittura delle texture o scolpire ogni decorazione, ma questo processo può richiedere ore per produrre un singolo pezzo e deve essere ripetuto da zero per ogni modello da decorare. D'altra parte, gli approcci automatici allo stato dell'arte si basano sull'approssimazione di questi processi con texturing basato su esempi o texturing procedurale, o con sistemi di riproiezione 3D. Tuttavia, questi approcci possono introdurre importanti limiti nei modelli utilizzabili e nella qualità dei risultati. Il nostro lavoro sfrutta invece i recenti progressi e miglioramenti delle prestazioni nel campo dell'elaborazione geometrica per creare modelli decorativi direttamente sulle superfici. Presentiamo una pipeline per i pattern 2D e una per quelli 3D, e dimostriamo come ognuna di esse possa ricreare una vasta gamma di risultati con minime modifiche dei parametri. Inoltre, studiamo la possibilità di creare modelli decorativi tangibili. I pattern 3D generati possono essere stampati in 3D e applicati a oggetti realmente esistenti precedentemente scansionati. Discutiamo anche la creazione di modelli con mattoncini da costruzione, e la possibilità di mescolare mattoncini standard e mattoncini custom stampati in 3D. Ciò consente una rappresentazione precisa indipendentemente da quanto la voxelizzazione sia approssimativa. I principali contributi di questa tesi sono l'implementazione di due diverse pipeline decorative, un approccio euristico alla costruzione con mattoncini e un dataset per testare quest'ultimo.The aim of this thesis is to develop effective tools to create digital decorative 3D artworks. Real-world art often involves the use of decorative patterns to enrich objects. These patterns can be painted on the base or might be realized with the application of small decorative elements. However, their creation in digital media is not trivial. On the one hand, users can manually perform texture paint or sculpt each decoration, in a process that can take hours to produce a single piece and needs to be repeated from the ground up for every model that needs to be decorated. On the other hand, automatic approaches in state of the art rely on approximating these processes with procedural or by-example texturing or with 3D reprojection. However, these approaches can introduce significant limitations in the models that can be used and in the quality of the results. Instead, our work exploits the recent advances and performance improvements in the geometry processing field to create decorative patterns directly on surfaces. We present a pipeline for 2D and one for 3D patterns and demonstrate how each of them can recreate a variety of results with minimal tweaking of the parameters. Furthermore, we investigate the possibility of creating decorative tangible models. The 3D patterns we generate can be 3D printed and applied to previously scanned real-world objects. We also discuss the creation of models with standard building bricks and the possibility of mixing standard and custom 3D-printed bricks. This allows for a precise representation regardless of the coarseness of the voxelization. The main contributions of this thesis are the implementation of two different decorative pipelines, a heuristic approach to brick construction, and a dataset to test the latter

CAD-integrierte Isogeometrische Analyse und Entwurf leichter Tragwerke

Isogeometric methods are extended for the parametric design process of complex lightweight structures. Three novel methods for the coupling of different structural elements are proposed: rotational coupling, implicit geometry description, and frictionless sliding contact. Moreover, the necessary steps for the integration of the numerical analysis, including pre- and post-processing, in CAD are investigated. It is possible to base several different analyses on each other in order to parametrically represent a construction process with multiple steps.Die isogeometrischen Methoden werden zur Anwendung im parametrischen Entwurfsprozess von komplexen Leichtbaustrukturen erweitert. Hierzu werden drei neue Methoden zur Kopplung unterschiedlicher Strukturelemente vorgeschlagen: Rotationskopplung, implizite Geometriebeschreibung und reibungsfreier Gleitkontakt. Ferner werden die nötigen Schritte zur Einbindung von Pre- und Postprocessing für numerische Simulationen in CAD untersucht. Mehrere unterschiedliche Analysen können auf einander folgen und werden verlinkt, um den Aufbauprozess in mehreren Schritten vollparametrisch abzubilden