Development Of Computer-aided Design Research Articles

Computer-Aided Design of X-Ray Microtomographic Scanners

The article is to study the development of computer-aided design of X-ray microtomography - the device for investigating the structure and construction three-dimensional images of organic and inorganic objects on the basis of shadow projections. This article provides basic information regarding CAD of X-ray microtomography and a scheme consisting of three levels. The article also shows basic relations of X-ray computed tomography, the generalized scheme of a X-ray microtomographic scanner. The methods of X-ray imaging of the spatial microstructure and morphometry of materials are described. The main characteristics of an X-ray microtomographic scanner, the X-ray source, X-ray optical elements and mechanical components of the positioning system are shown. The block scheme and software functional scheme for intelligent neural network system of analysis of the internal microstructure of objects are presented. The method of choice of design parameters of CADof X-raymicrotomography is aimed at improving the quality of design and reduce of costs of it. It is supposed to reduce the design time and eliminate the growing number of engineers involved in development and construction of X-ray microtomographic scanners.

Theoretical Modeling of Room Shape for Ray Tracing Simulation

With the recent developments in computer-aided design (CAD) technology, the detailed modeling of shapes has become routine. However, it is well known that low-frequency sounds do not propagate in detail-oriented models of rooms in the way that is predicted by geometrical acoustic simulations. Therefore, rough models of room shapes are commonly used and scattering coefficients are set for each material in this kind of simulation. However, scattering coefficients are difficult to use for creative room shape design, because scattering coefficients need to be measured in advance. Thus, we propose a new method for ray tracing simulations that can be used in place of the scattering coefficient method. This paper presents a discussion of methods for constructing the appropriate room shape for the analyzed frequency from a detail-oriented model of a room.

An AR-based hybrid approach for facility layout planning and evaluation for existing shop floors

Facility layout planning (FLP) has substantial impact on the various aspects of a manufacturing system. FLP is typically performed for new shop floors. However, enterprises nowadays are often faced with the need to reconfigure the existing shop floor layouts to synchronize the shop floor operations with the constantly changing production targets. FLP tasks for existing shop floors are often small in scale, e.g., adding or removing a couple of machines, but complex to address since a wide range of criteria need to be incorporated and the presence of the existing facilities imposes critical constraints. Current FLP approaches are not efficient to handle these issues. The development of computer-aided design (CAD) technology has provided feasible solutions to bridge this gap. In this paper, an augmented reality (AR)-based hybrid approach is proposed which facilitates on-site layout planning and evaluation in real time. By integrating AR technology with the mathematical modeling technique, the proposed approach allows the users to augment the shop floor with the facilities to be laid out, model the existing facilities to obtain their geometric data, and define the criteria and constraints to formulate the problems as multi-attribute decision-making (MADM) models. Two planning methods are employed to solve the MADM models, namely, information-aided manual planning and analytic hierarchy process (AHP)–genetic algorithm (GA)-based automatic planning. During the planning process, the criteria and the constraints are assessed in real time to provide immediate evaluation and feedback to facilitate decision-making.

Les implants sur mesure en reconstruction craniofaciale

The development of computer-aided design (CAD) technologies applied to biomaterials has allowed designing patient-specific implants perfectly adapted to the area to rebuild, and ensuring an easier, less invasive, and optimal reconstruction of the craniofacial skeleton. Custom-made implants, originally developed for the reconstruction of large cranial vault defects, were used to optimize cosmetic results, avoiding the morbidity related to donor site bone harvesting, or preventing frequent asymmetrical result due to peroperative biomaterial design. These implants thus proved very useful for facial skeleton reconstruction including for the orbital region. The preoperative computerized simulation made in collaboration with manufacturers allows optimizing reconstructions specifically for each patient.

Application of Multi-Objective Optimization Model in Design of Photovoltaic Architecture

With the increasingly serious crisis of the energy problem, all around the world, the application of solar energy has become an approach of solving the problem undoubtedly. In recent years, due to the rapid development of Chinese photovoltaic (PV) industry, the emergence of PV buildings is more and more widely in the domestic. The current trend is to apply Computer-Aided Design (CAD) software to realize the design of Building Integrated Photovoltaic (BIPV). The core problem of CAD is to obtain the best solution to a laying scheme of PV cell. In this paper, the design problem of PV building is concerned about. Through the research on the multi-objective optimization theory, it is to establish the model of multi-objective optimization that can meet these two objectives of the largest total annual solar photovoltaic power generation, yet the smallest possible the unit cost of power generation. The model can be solved by MATLAB using ideal point method. In order to detail explain the application of model and verify it, the design of PV cabin, in Datong area of Shanxi Province, is as an example. The study has laid the foundation for the development of CAD in the future.

Custom-made, root-analogue direct laser metal forming implant: a case report

In the last few years, the application of digital technology in dentistry has become widespread with the introduction of cone beam computed tomography (CBCT) scan technology, and considerable progress has been made in the development of computer-aided design/ computer-aided manufacturing (CAD/CAM) techniques, including direct laser metal forming (DLMF). DLMF is a technology which allows solids with complex geometry to be produced by annealing metal powder microparticles in a focused laser beam, according to a computer-generated three-dimensional (3D) model. For dental implants, the fabrication process involves the laser-induced fusion of titanium microparticles, in order to build, layer by layer, the desired object. At present, the combined use of CBCT 3D data and CAD/CAM technology makes it possible to manufacture custom-made, root-analogue implants (RAI) with sufficient precision. This report demonstrates the successful clinical use of a custom-made, root-analogue DLMF implant. CBCT images of a non-restorable right maxillary first premolar were acquired and transformed into a 3D model. From this model, a custom-made, root-analogue DLMF implant was fabricated. Immediately after tooth extraction, the RAI with a pre-operatively designed abutment was placed in the extraction socket and restored with a single crown. At the 1-year follow-up examination, the RAI showed a good functional and aesthetic integration. The introduction of DLMF technology signals the start of a new revolutionary era for implant dentistry as its immense potential for producing highly complex macro- and microstructures is receiving vast interest in different medical fields.

Strut size and surface area effects on long-term in vivo degradation in computer designed poly(l-lactic acid) three-dimensional porous scaffolds

Current developments in computer-aided design (CAD) and solid free-form fabrication (SFF) techniques enable fabrication of scaffolds with precisely designed architectures and mechanical properties. The present study demonstrates the effect of precisely designed three-dimensional scaffold architectures on in vivo degradation. Specifically, three types of porous poly(l-lactic acid) (PLLA) scaffolds with variable pore sizes, strut sizes, porosities, and surface areas fabricated by indirect SFF. In addition, one experimental group of PLLA solid cylinders was fabricated. The scaffolds and cylinders were subcutaneously implanted into mice for 6, 12 and 21weeks. The solid cylinders exhibited a faster percentage mass loss than all porous scaffolds. Among the porous scaffolds the group with the largest strut size lost percentage mass faster than the other two groups. Strong correlations between surface area and percentage mass loss were found at 12 (R2=0.681) and 21 (R2=0.671) weeks. Scaffold porosity, however, was not significantly correlated with degradation rate. Changes in molecular weight and crystallinity also resulted in changes in the chemical structures due to degradation, and the solid cylinders had faster crystallization due to more advanced degradation than the porous scaffolds. Scaffold compressive moduli decreased with degradation, but the resulting modulus was still within the lower range of human trabecular bone even after 21weeks. The loss in compressive moduli, however, was a complex function of both degradation and the initial scaffold architecture. This study suggests that CAD and fabrication, within a given material, can significantly influence scaffold degradation profiles.

Potential Use of Structural Layout Optimization at the Conceptual Design Stage

Despite recent developments in computer-aided design in architecture, both in terms of form generation techniques and performance-based design tools, there still appears to be polarization between the ‘visual’ and the ‘technical’ elements of design. Two causes of this are discussed: long-standing tradition within the discipline and perception of design as primarily a visual exercise. Structural layout optimization is a technique which enables automatic identification of optimal arrangements of structural elements in frames. As the technique appears to have the potential to help reduce the polarization between the visual and the technical elements of design, it can be considered as an ‘integrative’ form generation tool. Applications of the technique are considered via three design examples, demonstrating both its potential and areas where refinement is required before it is suitable for application in practice.

エルボおよびベンドを考慮した配管設計アルゴリズム

Nowadays, the pipe arrangement has been enabled to be more efficient and economical by development and spread of CAD (Computer-Aided Design). However, it is difficult to design a piping layout automatically because there are many regulations and functional design rules which must be satisfied. The authors propose an automatic routing method for simple pipes including elbows and bends. In a practical design of a piping layout, there are many bends connecting straight eccentric pipes which have gaps within the pipes' diameter. However, no precedence automatic piping algorithm has been taken into account pipelines with such bends. The proposed method finds piping routes making use of not only elbows but the bends in order to minimize costs of the path connecting start point to goal point, while avoiding obstacles such as structures, equipments and the other circuits. In this approach, the authors regard the piping route design problem as a routing problem in a directed and weighted graph. Note that the nodes in the proposed graph have state variables not only locations but directions of the pipes. This graph can easily express the bends as simple edges, and then the routing algorithm can easily handle the bends. In addition, the presented method has specifications that the sizes of each cell, which is generated by decomposing of a free space, are not restricted within the diameter of the pipe. The routing algorithm uses Dijkstra's method to provide candidate paths. The efficiency of the proposed method is demonstrated through several experiments

The Application Study in Computer Aided Design Based on the Hand-Drawn Performance

With the rapid development of computer-aided design, traditional hand-drawn performance undergoes a fundamental change. Since it has the characteristics of a variety of vivid, fast and convenient, the computer-aided design has become a new desinging trend. However, while the computer brings us conveniences, it also has many negative effects. Many designers rely on the computer-aided design excessively, and ignore the hand-drawn performance’s special advantages of enlightenning creative thinking, emphasizing the personality performance, promoting computer performances, and improving professional attainment. In the informationlized computer age, in order to better reflect the design’s essential connotation, we only have to combine the hand-drawn performance and the computer-aided design together perfectly, and coordinated development of the two should be the orientation of contemporary design.

Computer-Aided Design (CAD) and Environmental Art Design

Computer-aided design (CAD) poses a brand new change of environmental art design from concept to skills. Nowadays, computer operation is a must for environmental art design, and no one can ignore such a powerful trend. This is transition period from traditional manual design mode to advanced computer design mode, and now we are standing on top of this new start point. CAD has fully performed its charm and become an indispensable tool in the field of the environmental creative art design. Mastering relevant software has become an essential skill for designers. However they often feel lost in current complex computer software, or even when they have conquered software technology difficulties, still trapped into a hard-pressed embarrassment to combine design with ideas. This dissertation starts from CAD definition, discusses CAD development and its own characteristics, and further on CAD applications in environment art design, main types and functions in current CAD software. The end of this article also gives an outlook on future effects and scheme a better vision for CAD in environmental design.

Review of Design for Manufacturing and Assembly Aspects to Designing Modern Micro-Wave and Sheet Metal Products

In this paper, we present different points of view to make the sheet metal and micro-wave product as manufacturing friendly as possible. Within DFM(A)-research (Design for Manufacturing and Assembly), engineering design and manufacturability of Micro-Wave (MW) and sheet metal products has been studied. Other aspects of DFM(A) have risen from novel material applications and the development of CAD (Computer Aided Design) environments. In this paper, practical examples are presented to show how to apply DFMA-rules to MW- and sheet metal components, in particular, and how to develop DFM(A)-rules for these purposes.

Rapid parametric design methods for shoe-last customization

With the development of computer-aided design (CAD) technology and increasing demands of customized footwear, shoe-lasts are requested to be designed rapidly so as to speed-up the process of footwear manufacturing. Thus, this study presents a CAD system for shoe-last rapid customized design based on the piecewise reconstruction to realize the interactive deformation and separate/global shoe-last form reuse. First, piecewise remodeling method is proposed based on the multi-layer parametric definition and contour curves are extracted from the mesh. Then, five types of proper constraints to support surface manipulation are proposed, and the draft-driven deformation by the contour curve bending can realize the interactive local surface design in free angle of view. Finally, shoe-last styles can be saved and reused globally or separately to share design results between different shoe-lasts. Experimental examples show that customized shoe-lasts can be easily and rapidly generated by adopting the parametric design methods.

The Impact of Technology on Creativity in Design: An Enhancement?

Technology may be considered as an interface between individuals and the products they create, but we have to determine whether the use of new systems effectively enhance individuals' creative activities. In this paper, we present a new angle of reflection that we illustrate in the field of creative design, since it is a constant challenge for designers to introduce creativity in the projects they work on. The approach we propose is centred on designers' cognitive processes. We argue that both the development of new CAD (computer‐aided design) systems and their assessment should be conducted on the basis of a deep understanding of designers' cognitive processes. In accordance with this view, we present three empirical studies that were conducted in order to analyse the impact of new design support systems on designers' cognitive processes. Therefore, the results we present contribute to further our knowledge of whether new CAD technologies effectively facilitate designers' activities and enhance their creativity.

Computerised design of bone defect reconstruction in the maxillofacial region

Introduction: It is a challenge for oral and maxillofacial surgeons to precisely repair large defects in maxillary and mandibular bones. Although traditional surgical techniques can reconstruct the continuity of a bone defect, there is still a need for enhancing the precision of surgical procedures. Development of computer-aided design and object shape manufacture technique in recent years have improved the results of dental implant, bone defect repair and orthognathic surgery. Using rapid prototyping and reverse engineering, we have successfully treated 23 cases of defects or deformities in facial bones since 2002, and gained standard experiences.

Theoretical Research on Inheriting Degree in Appearance Design of Brand Products

In the appearance design of a product, the designer should combine his/her creative thinking with the industrial design approaches and skills to carry out the creative design from the aspects of product’s shape, color and texture, etc. However, from the viewpoint of the brand, a company or a product should have its own unique style of appearance. How to balance the creativity of designer and the original style is often a contradiction in product design. Based on this consideration, this paper presented a concept of Inheriting Degree (ID) in product appearance design. The visual characteristics of the product appearance were analyzed first and the hierarchical system for ID in product appearance design was established. The idiographic indexes of ID were given for a product’s appearance in shapes, colors and textures, respectively. By introducing set theory, the mathematical models were established and calculation formulae for each kind of ID were proposed. The results of this paper would provide a theoretical foundation for designer to generate design concepts in brand products. It also would provide a guideline for the development of computer aided design and evaluation system for the appearance design of brand products.

Complete-arch maxillary rehabilitation using a custom-designed and manufactured titanium framework: A clinical report

Fabrication of a passive framework when restoring multiple implants in an edentulous maxilla may be an important requisite for long-term implant survival. The development of computer-aided design and manufacturing techniques for fabricating custom 1-piece titanium frameworks can simplify that challenge. This article reports on a treatment in which a custom-milled titanium complete-arch maxillary framework was used to restore a compromised maxillary arch. A 4-year follow-up demonstrated a steady state of bone and no prosthodontic complications.

Constraint-Based Computer-Aided Design

Computer-aided design (CAD) systems have become parametric, basing shape design on constraints and design feature operations. We review the development of constraint-based parametric CAD, explaining some of the foundational issues as well as giving an outlook on possible future directions of development.

Transgression from drawing to making

Developments in computer-aided design and manufacturing are breaking down divisions between designing and making, opening up radical new opportunities for the practice of architecture.

Difficulties with the novices' comprehension of the computer-aided design (CAD) interface: Understanding visual representations of CAD tools

Visual representations of interfaces can affect users' abilities to comprehend the potential of their tools. Misunderstanding of the elements of the graphic user interface, such as icons, toolbars, dialogues and cursors, can become a barrier to an effective work. Software with the most complicated interface structures, such as computer-aided design (CAD) applications, may be possibly misused unless its visual elements are comprehensible. Designers' expectations can play a great role in comprehension of CAD tools. For that reason it is necessary to investigate users' needs to build a CAD interface reflecting the nature of how CAD users work. The paper presents the results of two experiments, carried out on the Faculty of Architecture, Technical University of Bialystok: forms with MicroStation® graphic user interface elements were presented to students who were asked to write about their perception of icons. The primary objectives of the experiments were to find out the beginners' awareness and expectations concerning CAD software, and to measure their discernment in using visual representations of CAD tools. Some ideas about shaping the structure of the graphic user interface were considered, such as selecting the interface background and the working commands . Results of the investigation can be applied to CAD development and to the field of human-computer interaction.