Reconstructing Polyhedral CAD Models by Recognizing Extrusion Features From Single-View Drawings

Author(s):  
Yong S. Suh

At the conceptual product design stage, designers prefer sketching initial design ideas on paper before using more sophisticated 3D CAD systems for their creativity and flexible design changes. At the later detailed design stages, however, precise 3D CAD modeling is a better choice for design analyses and downstream manufacturing applications. For an integrated digital product development, the 2D drawings need to be converted to 3D CAD models manually through some laborious and time-consuming processes. For decades, many researchers have contributed to the studies on reconstructing 3D geometric models from 2D sketches, but few describe constructing parametric feature-based CAD models that are currently widely used in the detailed design stages. In this paper, a procedure for constructing a feature-based 3D CAD model directly from a single-view 2D drawing is presented. The input sketch is assumed to be an exact orthogonal projection of a 3D model viewed at a general orientation. The model geometry is limited such that it can be constructed by a Boolean combination of extrusions of polygonal profiles.

Author(s):  
Satoshi Kanai ◽  
Taiga Higuchi ◽  
Yukiaki Kikuta

One of the critical issues of realizing human centered design (HCD) for information appliances is how to efficiently find the weakness of usability of the user interfaces (UI). At present, user test is the most reliable method of evaluating usability of UI. But executing user-test costs much due to fabrication of physical prototypes, securing of test subjects and facilities and the manual-based analysis of the test results. To solve the problems, we propose a computer-supported environment for testing and usability assessment for human centered-design of information appliances in the paper. In the environment, UI-operable 3D digital prototypes can be designed and used for user tests instead of physical prototypes, and the test results can be automatically analyzed to clarify the weak points of the UI design. UI-operable 3D digital prototypes can be modeled by integrating the state-transition-based UI behavior model with 3D CAD models of the housings. A function of graphically displaying user’s operational history helps the designers identify which portions in the UI specification induce wrong operations of users. A function of indicating digital questionnaire based on cognitive walkthrough method also enables them to reveal causes of the wrong operations and to clarify point of redesign. Comparison of the test results using different types of digital prototypes showed that the proposed UI-operable 3D digital prototype could fully replace the physical prototype in early design stage.


Author(s):  
Andrew Barclay ◽  
Jonathan Corney

Abstract An experienced engineer can glance at a component and suggest appropriate methods for its manufacture. This skill has been difficult to automate but in recent years Neural Networks have demonstrated impressive image recognition capabilities in many applications. Consequently, this work is motivated by the goal of automating shape assessment for manufacturing. Specifically the reported work investigates the feasibility of training a convolutional neural network (CNN) to recognize 2D images of shapes associated with particular Near Net Shape (NNS) manufacturing processes such as casting, forging, or flow forming. The system uses multiple images generated from 3D CAD models (each manually associated with specific NNS processes) as training data and a single shop floor photograph as a classification query. While multiple views are used to train the CNN only a single view is used to assess the accuracy of the classification. Such single-view classification is designed to support the easy assessment of physical parts observed in manufacturing facilities where it would often be impractical to create an array of images from many viewpoints. The result suggests that despite limitations, single-view CNNs can classify real engineering components for manufacture.


Author(s):  
Thiago Weber Martins ◽  
Lars Niemczik ◽  
Reiner Anderl

This paper introduces a concept to integrate measurements data into feature-based 3D CAD models. The concept focuses on its application in the measurement of bifurcated sheet metal profiles. For that, an interface to read and import this data into the CAD system is developed. Since the measurement data is stored as a point cloud, further data processing (reverse engineering) is necessary to recreate the work piece shape in the CAD system. If the measured work piece model and the CAD model of the design piece are available, an automated comparison of the defined dimension takes place. The result is a notification in the CAD model indicating which dimension deviates from the target values. Use-cases are elaborated for integrating the concept in the product development process. To implement this concept, an experimental setup is built up consisting of a measurement system and 3D CAD system. The COPRA ProfileScan Desktop is used to measure the profile. Siemens NX 11 is the chosen CAD system. Based on this setup, the concept is validated on a manufactured profile.


Author(s):  
Soonjo Kwon ◽  
Byung Chul Kim ◽  
Duhwan Mun ◽  
Soonhung Han

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.


2021 ◽  
Vol 11 (4) ◽  
pp. 145
Author(s):  
Nenad Bojcetic ◽  
Filip Valjak ◽  
Dragan Zezelj ◽  
Tomislav Martinec

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.


Author(s):  
Arivazhagan Pugalendhi ◽  
Rajesh Ranganathan

Additive Manufacturing (AM) capabilities in terms of product customization, manufacture of complex shape, minimal time, and low volume production those are very well suited for medical implants and biological models. AM technology permits the fabrication of physical object based on the 3D CAD model through layer by layer manufacturing method. AM use Magnetic Resonance Image (MRI), Computed Tomography (CT), and 3D scanning images and these data are converted into surface tessellation language (STL) file for fabrication. The applications of AM in ophthalmology includes diagnosis and treatment planning, customized prosthesis, implants, surgical practice/simulation, pre-operative surgical planning, fabrication of assistive tools, surgical tools, and instruments. In this article, development of AM technology in ophthalmology and its potential applications is reviewed. The aim of this study is nurturing an awareness of the engineers and ophthalmologists to enhance the ophthalmic devices and instruments. Here some of the 3D printed case examples of functional prototype and concept prototypes are carried out to understand the capabilities of this technology. This research paper explores the possibility of AM technology that can be successfully executed in the ophthalmology field for developing innovative products. This novel technique is used toward improving the quality of treatment and surgical skills by customization and pre-operative treatment planning which are more promising factors.


2021 ◽  
Vol 1 ◽  
pp. 3199-3208
Author(s):  
Emanuel Balzan ◽  
Pierre Vella ◽  
Philip Farrugia ◽  
Edward Abela ◽  
Glenn Cassar ◽  
...  

AbstractResearch funded projects are often concerned with the development of proof-of-concept products. Consequently, activities related to verification and validation testing (VVT) are often not considered in depth, even though various design iterations are carried out to refine an idea. Furthermore, the introduction of additive manufacturing (AM) has facilitated, in particular, the development of bespoke medical products. End bespoke products, which will be used by relevant stakeholders (e.g. patients and clinicians) are fabricated with the same manufacturing technologies used during prototyping. As a result, the detailed design stage of products fabricated by AM is much shorter. Therefore, to improve the market-readiness of bespoke medical devices, testing must be integrated within the development from an early stage, allowing better planning of resources. To address these issues, in this paper, a comprehensive VVT framework is proposed for research projects, which lack a VVT infrastructure. The framework builds up on previous studies and methods utilised in industry to enable project key experts to capture risks as early as the concept design stage.


2012 ◽  
Vol 26 (10) ◽  
pp. 3201-3212 ◽  
Author(s):  
Sang-Uk Cheon ◽  
Duhwan Mun ◽  
Soonhung Han ◽  
Byung Chul Kim

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