In this paper, we widen the naming problem studies to the rulebased graph transformation modeling systems. We propose a persistent naming method taking advantage of the generalized maps’ and graph transformation rules’ formalization of operations. It enables a unique and homogeneous characterisation of entities in all dimensions. Most existing methods require tracking numerous topological entities and consider the persistent naming problem only from the parameters’ modifications of a parametric specification standpoint. With our solution, not only the naming problem is tackled within the usual framework of parameters edition, but we also take the specification edition into account (addition, deletion and displacement of operations). Moreover, our solution makes use of directed acyclic graphs to represent the histories of topological entitiesand to track only the entities used in the parametric specification and the ones they originate from.

The process of motorcycle seat styling is a grey system with partially known and partially unknown information and is influenced by various factors.In this study, Grey Modelling (GM)(1,1) is used to predict the style of a motorcycle seat, and the shape features of the seat are extracted via morphological analysis and are parameterized.The process of shape evolution is established, and the modelling characteristics are predicted by GM(1,1).The kansei study is performed using five adjectives describing the seat styles to establish the equation of kansei regression analysis.The regression analysis is employed to modify predictive modelling.A certain brand of motorcycle seats is modelled to analyse and verify the feasibility and scientific applicability of adopting GM(1,1) in predicting motorcycle seat styling, which provided a feasible and effective reference for the motorcycle seat design.

3D modeling for Archaeology requires to easily model scenes by letting users evaluate a parametric specification of archaeology-oriented gestures, then modify and reevaluate the specification to produce various restitution hypotheses. But the current modeling tools that support reevaluation mechanisms are not dedicated to Archaeology. The Jerboa library, based on graph transformations rules, is well suited for creating operations fitting the needs of archaeologists. But it does not any support reevaluation mechanism and especially the persistent naming system, that is used to identify the entities of the initial model and match them with entities of the reevaluated model. In this paper, we extend Jerboa with a new application-independent persistent naming model, which is more general and homogeneous than other solutions found in the literature and is the first one to handle parametric specification edition.

The crucial issue in Knowledge-Based Engineering is representation of expert knowledge in a readable way for both a computer agent and human.Properly prepared knowledge (captured, assessed, formalized and structured) plays an important role for success of every knowledge based system; particularly in the discipline of machinery design.Many knowledge model properties are of great significance, in addition to formal structure and consistency, reusability, flexibility, interoperability of knowledge model are also becoming increasingly essential for the knowledge-based systems research community.This paper presents a hybrid knowledge representation for solving deductive engineering tasks in Knowledge Based Machinery Design.We propose two different methods for storing engineering knowledge; as a repository for declarative knowledge, an ontological knowledge based was applied; for procedural knowledge storage as a formal representation, a geometrical model was used.Apart from theoretical foundations the work is also concerned with presenting and discussing an industrial application of the above-mentioned knowledge representation.As a practical part an application for engineer supporting in design process of dies with non-cutting shape forming in automotive field is indicated.This part deals with problems, challenges and bottlenecks coming up during developing process that application and shows advantages and disadvantages of this knowledge representation.For carrying out the effort CATIA V5 as Computer Aided Design system was applied.To fulfill the knowledge model requirements, especially reusability, flexibility and inter-operability, Protégé as an ontology editor and knowledge-based framework with OKBC (Open Knowledge Base Connectivity) protocol was used.

In current feature-based parametric design systems, the reusability principle is not as fully supported as it should be. Both unpredictability and ambiguity of models often happen during design modification within one system. This reference deficiency significantly reduces the power of feature-based parametric modeling, where geometry reevaluation generates some unexpected topology, especially when considering edges. We propose in this paper a new edge matching method resulting from the intersection of non-planar faces. This method considers the matching between edges as a geometric transformation which overlays edges of the initial model on edges of the reevaluated model. It finds, among all possible edge mappings, the one which represents the design intent as close as possible. In order to find the right mapping, it quantifies the relevance of each mapping. Moreover, in addition to the edges resulting from the intersection of the same pair of faces, this method uses "virtual edges" for solving some ambiguous cases.

Hierarchical representations, such as irregular pyramids, are the bases of several applications in the field of discrete imagery. So, n-dimensional ”bottom-up” irregular pyramids can be defined as stacks of successively reduced n-dimensional generalized maps (n-G-maps) [11], each n-G-map being defined from the previous level by using removal and contraction operations defined in [8]. Our goal is to build a theoretical framework for defining and handling n-dimensional ”top-down” irregular pyramids. To do so, we propose in this paper to study the definition of both insertion and expansion operations that allow to conceive these kinds of pyramids.

Nowadays, many commercial CAD systems are built on proprietary geometric kernel which provide an API containing a set of high level geometric operations (boolean operations, slot, chamfering, etc). Because of their complexity, these operations can generate important modifications on topological cells (vertices, edges, faces, volumes, etc.) of the objects. At the same time, many of these kernels need to know precisely what has occurred to each topological cell belonging to objects given or resulting from a previous high level geometric operation. At the end of each operation, the geometric kernel must provide a bulletin board describing cells' evolution through a list of events (split, merge, creation, deletion). Most commercial geometric kernels use B-Rep structures and provide methods enabling the developer of a CAD system to retrieve a number of events that occurred on cells. These kernels have their own scheme for detecting events, based on their own taxonomy of situations, heuristics and evolution rules. Little is known of their details, which are proprietary information, let alone of the underlying theory, if any. Generally, for example, the detected events are not generic for all cells' dimensions. This lack of underlying theory limits the possibility to extend the use of these kernels to new domains of investigation. In this paper, we propose a generic model that enables to create a bulletin board. This bulletin board will contain the complete list of events having occurred on cells of any dimension, and that belong to any topological model. The genericity of this model and the completeness in all dimensions of this list are based on the use of four elementary mechanisms (split_elem, merge_elem, crea_elem, del_elem). They are defined independently of the topological model, and allow the generation of the bulletin board, whatever the geometric operation. This model has been implemented using the geometric kernel of the modeler Moka, based on generalized maps.

Nowadays, many commercial CAD systems support history-based, constraint-based and feature-based modeling. Unfortunately, most systems fail during the re-evaluation phase when various kind of topological changes occur. This issue is known as "persistent naming" which refers to the problem of identifying entities in an initial parametric model and matching them in the re-evaluated model. Most works in this domain focus on the persistent naming of atomic entities such as vertices, edges or faces. But very few of them consider the persistent naming of aggregates like shells (connected set of faces). We propose in this paper a complete framework for extending a persistent naming model of atomic entities in order to identify and match any kind of shells based on their underlying topology.

In this paper, we present a survey of existing approaches on persistent naming in parametric system. We identify five common concepts that may be found in most of the studies. We propose two orthogonal criteria for classifying persistent naming approaches. This survey is intended to represent a state of the art of robust parametric reevaluation of geometric models.

Nowadays, many commercial CAD systems support history-based, constraint-based and feature-based modelli ng. The use of these new capabiliti es raises the issue of persistent naming which refers to the problem of identifying entities in an initial parametric model and matching them in the re-evaluated model. The goal of this paper in to propose a naming mechanism and an hierarchical structure enabling to identify topological entities and to apprehend the "design intent".

In recent years, history-based, constraint-based and feature-based CAD systems (often gathered under the generic name of parametrics), appeared as a major progress both to express and to capture conceptual designs and design intents. This deployment raise two major issues. The first one is to define a data model that provides for exchange capabilities between heterogeneous CAD systems and for archiving. The second one is the well known “topological naming” problem. The goal of this paper is to propose an unified modeling framework for parametric data, that addresses these two issues. This framework, defined in the object-flavored EXPRESS data specification language, involves a three layers architecture. Gathering the complete definition of a parametric object in the same data model permits both to simplify the data-management, and to define a neutral description of parametrics, enabling exchange between heterogeneous CAD systems.

Les objets non varietes, connus encore sous le terme non-manifold, presentent la particularite d'avoir des points frontieres dont les voisinages relatifs ne sont pas homeomorphes a des demi-boules. Cet article propose un formalisme, nomme modele Radial, pour la representation des objets non varietes comme des complexes cellulaires. Un noyau d'operateurs topologiques est elabore pour la construction et la manipulation des objets, decrits dans les termes du modele Radial.

Processing non-manifold topologies (abbreviated as NMT) plays a primary role in current development of solid modeling applications. Euler operators are a powerful tool for creation of valid boundary representations of solids. By contrast with the manifold domain, where topological operators are well understood and implemented, there is a lack of elaboration of their non-manifold counterparts. In this paper we work out a basis of Euler-like operators for construction, maintenance and manipulation of boundary schemes of non-manifold objects. The presented algorithms are implemented for a NMT data structure and experimental results are discussed in the context of the completeness and soundness of the NMT operators. 1 State of the art A crucial point in current theory and practice of geometric modeling 9] is the representation and manipulation of dimensionally unhomogeneous objects known as non-manifolds. 1 The basic assumption underlying solid modeling, that models are valid i.e. correspond to valid solid objects, implies complex veriication tests, especially when non-manifolds are proceeded. The preservation of boundary model validity in the course of NMT object construction and modiication is a central issue in the actual study. Two representative results are discussed. MM antyll a's work 8] is concerned with manifold boundary schemes while Weiler's work 12, 11] advocates the non-manifold ones. As it is shown by 8] the topological integrity of boundary representations deened over the the manifold domain can be enforced by simply structural means. For this purpose plane models 2 are used as the mathematical abstraction for the boundary representational schemes. The interest is directed towards the plane models that 1 A n-manifold is a topological space where every point has a neighborhood topologically equivalent to D n (x; r) = fy 2 R n : kx ? yk < rg: 2 A plane model is a planar directed graph fV;E; Fg with a nite number of vertices V , edges E and faces F bounded by edges and vertices. Each face of the graph has a certain orientation around its edges and vertices. Faces, edges and vertices are labeled; if a collection of edges or vertices has the same label, they are identiied.

The focus of current researches in geometric modelling is the extension of the representational power in order to encompass the non-manifold objects. In the present paper a non-manifold boundary representation is proposed. New types of topological elements are introduced to extend the dimension of the non-manifold condition at a face. This structure is based on the theory of simplicial complexes. The technique used for construction and manipulation of objects ensures the model validity at each intermediate stage of the design. An undergrounding set of basic operators is developed that according to empirical results is a complete and suucient set for manipulation of objects described in terms of the elaborated structure.