scholarly journals Automatized Evaluation of Students’ CAD Models

2021 ◽  
Vol 11 (4) ◽  
pp. 145
Author(s):  
Nenad Bojcetic ◽  
Filip Valjak ◽  
Dragan Zezelj ◽  
Tomislav Martinec
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Computer Application ◽  
Test Cases ◽  
Cad Model ◽  
Computer Solution ◽  
3D Cad ◽  
Computer Aided ◽  
Cad Models ◽  
Aided Design

The article describes an attempt to address the automatized evaluation of student three-dimensional (3D) computer-aided design (CAD) models. The driving idea was conceptualized under the restraints of the COVID pandemic, driven by the problem of evaluating a large number of student 3D CAD models. The described computer solution can be implemented using any CAD computer application that supports customization. Test cases showed that the proposed solution was valid and could be used to evaluate many students’ 3D CAD models. The computer solution can also be used to help students to better understand how to create a 3D CAD model, thereby complying with the requirements of particular teachers.

Graph-Based Simplification of Feature-Based Three-Dimensional Computer-Aided Design Models for Preserving Connectivity

2015 ◽  
Vol 15 (3) ◽  
Author(s):  
Soonjo Kwon ◽  
Byung Chul Kim ◽  
Duhwan Mun ◽  
Soonhung Han
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Evaluation Metrics ◽  
Prototype System ◽  
Cad Model ◽  
3D Cad ◽  
Computer Aided ◽  
Cad Models ◽  
Feature Based ◽  
Aided Design

The required level of detail (LOD) of a three-dimensional computer-aided design (3D CAD) model differs according to its purpose. It is therefore important that users are able to simplify a highly complex 3D CAD model and create a low-complexity one. The simplification of a 3D CAD model requires the application of a simplification operation and evaluation metrics for the geometric elements of the 3D CAD model. The evaluation metrics are used to select those elements that should be removed. The simplification operation removes selected elements in order to simplify the 3D CAD model. In this paper, we propose the graph-based simplification of feature-based 3D CAD models using a method that preserves connectivity. First, new evaluation metrics that consider the discrimination priority among several simplification criteria are proposed. Second, a graph-based refined simplification operation that prevents the separation of a feature-based 3D CAD model into multiple volumes is proposed. Finally, we verify the proposed method by implementing a prototype system and performing simplification experiments using feature-based 3D CAD models.

A novel method for early formal developments using computer aided design and rapid prototyping technology

2003 ◽  
Vol 217 (5) ◽  
pp. 695-698 ◽  
Author(s):  
P A Prieto ◽  
D K Wright ◽  
S F Qin
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Rapid Prototype ◽  
Physical Models ◽  
Prototype Model ◽  
Cad Model ◽  
Computer Aided ◽  
Cad Models ◽  
Novel Method ◽  
Aided Design

The paper describes a novel method for updating computer aided design (CAD) models with information taken from physical models in the early stages of design. The new approach is an image mapping based method in which an initial. CAD model is transferred to a soft rapid prototype model (RPM) made by a three-dimensional printer and sculpted in order to carry out formal developments. The RPM has a built-in contrasting three-dimensional grid composed of parallel orthogonal planes, and the initial CAD model is represented by cross-section curves corresponding to the RPM grid. The initial CAD geometry is then updated from images of the developed RPM by matching the differences between the initial CAD model and the modified RPM, making use of identical perspective transformations and viewpoints for the initial CAD model and an RPM image. Examples studied varied from a small depression on a cube face to general freeform surfaces. Compared with typical reverse engineering (RE) processes, the present approach is simpler and more direct. It is not necessary to use three-dimensional scanning or coordinate measuring devices for updating existing initial geometrical CAD models with data obtained from physical models.

Laser Additive Manufacturing

3D Printing ◽  
2017 ◽  
pp. 154-171 ◽  
Author(s):  
Rasheedat M. Mahamood ◽  
Esther T. Akinlabi
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Process ◽  
Computer Aided Design ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Cad Model ◽  
Laser Additive Manufacturing ◽  
Computer Aided ◽  
Manufacturing Technologies ◽  
Aided Design

Laser additive manufacturing is an advanced manufacturing process for making prototypes as well as functional parts directly from the three dimensional (3D) Computer-Aided Design (CAD) model of the part and the parts are built up adding materials layer after layer, until the part is competed. Of all the additive manufacturing process, laser additive manufacturing is more favoured because of the advantages that laser offers. Laser is characterized by collimated linear beam that can be accurately controlled. This chapter brings to light, the various laser additive manufacturing technologies such as: - selective laser sintering and melting, stereolithography and laser metal deposition. Each of these laser additive manufacturing technologies are described with their merits and demerits as well as their areas of applications. Properties of some of the parts produced through these processes are also reviewed in this chapter.

Toward Effective Mechanical Design Reuse: CAD Model Retrieval Based on General and Partial Shapes

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Min Li ◽  
Y. F. Zhang ◽  
J. Y. H. Fuh ◽  
Z. M. Qiu
Keyword(s):  
Computer Aided Design ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Cad Model ◽  
Model Retrieval ◽  
Cad Models ◽  
Feature Based ◽  
Novel Method ◽  
Aided Design ◽  
Model Similarity

In product design, a large proportion of three-dimensional (3D) computer-aided design (CAD) models can be reused to facilitate future product development due to their similarities in function and shape. This paper presents a novel method that incorporates modeling knowledge into CAD model similarity assessment to improve the effectiveness of reuse-oriented retrieval. First, knowledge extraction is performed on archived feature-based CAD models to construct feature dependency directed acyclic graph (FDAG). Second, based on the FDAG subgraph decomposition, two useful component partitioning approaches are developed to extract simplified essential shapes and meaningful subparts from CAD models. Third, the extracted shapes and their FDAG subgraphs are indexed. Finally, the indexed shapes that are similar to user-sketched queries are retrieved to reuse, and FDAG information of the retrieved shapes is provided as redesign suggestions. Experimental results suggest that the incorporation of modeling knowledge greatly facilitates CAD model retrieval and reuse. Algorithm evaluations also show the presented method outperforms other 3D retrieval methods.

An Automatic Technique for CAE Analysis With a 3D-CAD Model

2002 ◽  
Author(s):  
Norihiko Nonaka ◽  
Ichirou Nishigaki
Keyword(s):  
Computer Aided Design ◽  
Geometric Model ◽  
Three Dimensional ◽  
Analysis Time ◽  
Cad Model ◽  
3D Cad ◽  
Computer Aided ◽  
Cae Analysis ◽  
Analysis System ◽  
Definition Of

A CAE (computer-aided engineering) analysis system, consisting of a 3D-CAD (three-dimensional computer-aided design) modeler, a pre-processor, an analysis solver, and a post-processor, was developed. This system uses automated procedures for solid modeling, definition of analysis models (i.e., defining boundary conditions and material properties, traditionally done manually), mesh generation, numerical simulation, and visualization of results. The CAE analysis system has two key features: it can greatly reduce the analysis time, and it uses a 3D-CAD model as the geometric model for numerical analysis. It was found that the developed automatic system reduces the analysis time by 50% compared with that for manual operation.

Virtual concurrent product development of plastic injection moulds

2000 ◽  
Vol 214 (2) ◽  
pp. 165-168 ◽  
Author(s):  
G Britton ◽  
T S Beng ◽  
Y Wang
Keyword(s):  
Product Development ◽  
Collaborative Design ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Prototype System ◽  
Computer Aided ◽  
Cad Cam ◽  
Cad Models ◽  
Aided Design ◽  
Plastic Injection

This paper describes three approaches for virtual product development of plastic injection moulds. The first is characterized by the use of three-dimensional computer aided design (CAD) for product design, two-dimensional drafting for mould design and three-dimensional computer aided design/manufacture (CAD/CAM) for mould manufacture. The second is characterized by the use of three-dimensional CAD models by all three participants, but between any two participants some form of file conversion is normally required because different CAD systems are used. The first two approaches share one common feature: the models are passed serially from the product designer to the mould designer and on to the toolmaker. They represent current practice in industry. The third approach is a proposed collaborative design process. Participants can work concurrently on the same model, sharing their knowledge and experience. The process is currently being refined and will be validated later this year with a prototype system based on Unigraphics iMAN software.

A Methodology for Building Up an Infrastructure of Haptically Enhanced Computer-Aided Design Systems

2008 ◽  
Vol 8 (4) ◽  
Author(s):  
Weihang Zhu
Keyword(s):  
Computer Aided Design ◽  
Force Feedback ◽  
Haptic Rendering ◽  
Haptic Interface ◽  
Cad Systems ◽  
3D Cad ◽  
Cad System ◽  
Computer Aided ◽  
Cad Models ◽  
Aided Design

This paper presents an infrastructure that integrates a haptic interface into a mainstream computer-aided design (CAD) system. A haptic interface, by providing force feedback in human-computer interaction, can improve the working efficiency of CAD/computer-aided manufacturing (CAM) systems in a unique way. The full potential of the haptic technology is best realized when it is integrated effectively into the product development environment and process. For large manufacturing companies this means integration into a commercial CAD system (Stewart, et al., 1997, “Direct Integration of Haptic User Interface in CAD Systems,” ASME Dyn. Syst. Control Div., 61, pp. 93–99). Mainstream CAD systems typically use constructive solid geometry (CSG) and boundary representation (B-Rep) format as their native format, while internally they automatically maintain triangulated meshes for graphics display and for numerical evaluation tasks such as surface-surface intersection. In this paper, we propose to render a point-based haptic force feedback by leveraging built-in functions of the CAD systems. The burden of collision detection and haptic rendering computation is alleviated by using bounding spheres and an OpenGL feedback buffer. The major contribution of this paper is that we developed a sound structure and methodology for haptic interaction with native CAD models inside mainstream CAD systems. We did so by analyzing CAD application models and by examining haptic rendering algorithms. The technique enables the user to directly touch and manipulate native 3D CAD models in mainstream CAD systems with force/touch feedback. It lays the foundation for future tasks such as direct CAD model modification, dynamic simulation, and virtual assembly with the aid of a haptic interface. Hence, by integrating a haptic interface directly with mainstream CAD systems, the powerful built-in functions of CAD systems can be leveraged and enhanced to realize more agile 3D CAD design and evaluation.

Interdisciplinary and Consistent Use of a 3D CAD Model for CAx Education in Engineering Studies

2016 ◽  
Author(s):  
Andreas Faath ◽  
Reiner Anderl
Keyword(s):  
Computer Aided Design ◽  
Mechanical Engineering ◽  
Project Based Learning ◽  
Cad Model ◽  
Process Chain ◽  
3D Cad ◽  
Engineering Studies ◽  
Process Chains ◽  
Computer Aided ◽  
Aided Design

Computer Aided Design (CAD) represents one of the key lectures in the studies of mechanical and process engineering as well as several other engineering disciplines. Furthermore Computer Aided x (CAx) systems are firmly established in the product development process. A new concept of teaching for engineering studies at the Technical University of Darmstadt (TU Darmstadt) derived by project based learning is introduced using CAx process chains i.e. the CAD-Multi Body Simulation (MBS) process chain. For the first time in engineering degree a 3D CAD model is consistently used by different process chains in multiple lectures and exercises during the whole engineering study. The early integration of this 3D CAD model in the second semester lays a foundation for its usage in further lectures, courses, projects and theses. Due to the fact, that this 3D CAD model embodies a university groups’ race car, students are able to deepen their knowledge within the university group “TU Darmstadt Racing Team e.V. (DART)”. Therefore, synergies between private and student activities are promoted, e.g. students acquire knowledge about automotive engineering. Besides the virtual implementation and validation, concepts can use the prototype for implementation and validation. The suitability of the 3D CAD model for CAD education in engineering studies especially the modelling and assembling of parts and assemblies is validated by the coached exercise of the course “Computer Aided Design”. The design education of students with mechanical engineering orientated fields of studies is held as a mandatory course in the second semester of mechanical engineering degrees at TU Darmstadt since 1995 and is solely taught with modern 3D CAD Systems. The MBS process chain is validated by several projects and theses using the McNeil Swendler Corp. (MSC) Software Automated Dynamic Analysis of Mechanical Systems (ADAMS) Car. Students run MBS by using the 3D CAD model. Besides driving maneuvers, stamp tests are simulated. In this context the entire MBS process chain is passed. The 3D CAD model serves as a basis for structures, geometry and the representation of kinematic chains, guided by the 3D CAD models geometry.

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