Verification of Scanned Engineering Parts with CAD Models Based on Discrete Curvature Estimation

2005 ◽  
Vol 5 (2) ◽  
pp. 116-117 ◽  
Author(s):  
B. Lipshitz ◽  
A. Fischer
Keyword(s):  
Manufacturing Industry ◽  
Real Data ◽  
Current Work ◽  
Cad Model ◽  
Sampled Data ◽  
Discrete Curvature ◽  
Cad Models ◽  
Curvature Estimation ◽  
Prototype Design

The manufacturing industry constantly needs to verify machined objects against their original CAD models. Given a prototype design, an engineer should be able to determine whether the part was manufactured well; that is, whether it fits the CAD model exactly. However, derivative computations are unstable for real data, and the estimated curvature is thus very sensitive to noise. Moreover, in many cases, spatial fitting of corresponding points is not sufficient. The current work utilizes the curvature properties to inspect manufactured parts that have been reconstructed from noisy and densely sampled data.

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.

A 3D CAD model input pipeline for REFMUL3 full-wave FDTD 3D simulator

2021 ◽  
Vol 16 (11) ◽  
pp. C11013
Author(s):  
J.M. Santos ◽  
E. Ricardo ◽  
F.J. da Silva ◽  
T. Ribeiro ◽  
S. Heuraux ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Thermal Protection ◽  
Interface Problem ◽  
Cad Model ◽  
Fusion Plasma ◽  
3D Cad ◽  
Full Wave ◽  
Wall Structures ◽  
Design Cycle ◽  
Cad Models

Abstract The use of advanced simulation has become increasingly more important in the planning, design, and assessment phases of future fusion plasma diagnostics, and in the interpretation of experimental data from existing ones. The design cycle of complex reflectometry systems, such as the ones being planned for next generation machines (IDTT and DEMO), relies heavily on the results produced by synthetic diagnostics, used for system performance evaluation and prediction, both crucial in the design process decision making. These synthetic diagnostics need realistic representations of all system components to incorporate the main effects that shape their behavior. Some of the most important elements that are required to be well modelled and integrated in simulations are the wave launcher structures, such as the waveguides, tapers, and antennas, as well as the vessel wall structures and access to the plasma. The latter are of paramount importance and are often neglected in this type of studies. Faithfully modelling them is not an easy task, especially in 3D simulations. The procedure herein proposed consists in using CAD models of a given machine, together with parameterizable models of the launcher, to produce a description suited for Finite Difference Time Domain (FDTD) 3D simulation, combining the capabilities of real-world CAD design with the power of simulation. However, CAD model geometric descriptions are incompatible with the ones used by standard FDTD codes. CAD software usually outputs models in a tessellated mesh while FDTD simulators use Volumetric Pixel (VOXEL) descriptions. To solve this interface problem, we implemented a pipeline to automatically convert complex CAD models of tokamak vessel components and wave launcher structures to the VOXEL input required by REFMUL3, a full wave 3D Maxwell FDTD parallel code. To illustrate the full procedure, a complex reflectometry synthetic diagnostic for IDTT was setup, converted and simulated. This setup includes 3 antennas recessed into the vessel wall, for thermal protection, one for transmission and reception, and two just for reception.

An Automated System for Design for Manufacturability Analysis for Die-Casting

2018 ◽  
Author(s):  
Sunil Kumar ◽  
Jatinder Madan
Keyword(s):  
Die Casting ◽  
Automated System ◽  
Design For Manufacturability ◽  
Design Stage ◽  
Present System ◽  
Cad Model ◽  
Cast Part ◽  
Early Design Stage ◽  
Die Cast ◽  
Cad Models

Design for manufacturing (DFM) is an important concept that helps to incorporate manufacturability considerations at early design stage. Development of automated DFM tools has become important especially when design and manufacturing are being done by different teams often distantly located. An automated system for design for manufacturability analysis for die-cast parts has been presented in this paper. The paper discusses: (i) knowledgebase of DFM guidelines (ii) die casting feature extraction from part CAD model, and (iii) automated system for DFM analysis and model updation of the die-cast part CAD model. The capabilities of the system are demonstrated by applying it on die cast part CAD models. The results have been validated with the industrial experts. The present system works with CAD models having features such as boss, rib, hole and draft, created using feature based modeling.

Representation of Burr Information in CAD Models

1999 ◽  
Author(s):  
Uma Jayaram ◽  
David Cramer ◽  
Narayanan Mathrubutham
Keyword(s):  
Manufacturing Processes ◽  
Cad Model ◽  
Size Information ◽  
Cad Models ◽  
Master Model ◽  
Physical Part ◽  
The Cost ◽  
Program Interface

Abstract Burr removal and deburring can often account for as much as one-third the cost of producing a part. Much attention is being focussed on integrating the deburring process into the product and manufacturing processes. Consequently there is a need for a system which can represent burr information in the CAD model as part of the product “master” model. In this paper, we present a method to capture burr information from the physical part and integrate that information with the CAD model of the part. Burr location and size information were recorded for the physical part. Methods were developed to encapsulate this information automatically in the CAD model through the applications program interface. This information was used to automatically create NC operations and sequences for downstream deburring.

Geometric Reasoning for the Coding of CAD Models

1995 ◽  
Author(s):  
A. Z. Qamhiyah ◽  
B. Benhabib ◽  
R. D. Venter
Keyword(s):  
Computer Aided Design ◽  
Feature Recognition ◽  
Effective Means ◽  
Boundary Representation ◽  
Cad Model ◽  
Cad System ◽  
Cad Models ◽  
Form Features ◽  
Feature Based Design ◽  
Design Retrieval

Abstract Many of today’s concurrent product-development cycles depend on the utilization of intelligent Computer-Aided Design (CAD) systems. Thus, it would be essential to provide CAD users with effective means for interacting with the CAD system and its database. This paper addresses the development of a boundary-based coding procedure for CAD models. Coding the geometric and processing characteristics of objects, based on their CAD model representation, has been long recognized as an effective approach that allows convenient design retrieval on the one hand and process-planning automation on the other. Our work is based on the assumption that form features are recognizable and extractable from the CAD model by current feature-recognition, feature extraction and feature-based-design approaches. The coding procedure is applicable to the boundary representation of the object and its extracted form features.

scholarly journals A Novel Method for nZEB Internal Coverings Design Based on Neural Networks

Coatings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 288 ◽  
Author(s):  
José A. Orosa ◽  
Diego Vergara ◽  
Ángel M. Costa ◽  
Rebeca Bouzón
Keyword(s):  
Building Materials ◽  
International Energy Agency ◽  
Construction Materials ◽  
Real Data ◽  
Point Of View ◽  
Building Construction ◽  
Sampled Data ◽  
Energy Agency ◽  
Vapour Permeability ◽  
Weather Changes

Research from the International Energy Agency about indoor ambiences and nearly zero energy buildings (nZEB) in the past has been centred on different aspects such as the prediction of indoor conditions as a function of the weather using laboratory material properties for simulations and real sampled data for validation. Thus, it is possible to use real data for defining behavioural groups of indoor ambiences as a function of real vapour permeability of internal coverings. However, this method is not suitable for modelling it and predicting its behaviour under weather changes, which is of interest to improve the method of selection and use of building construction materials. In this research, artificial intelligence procedures were employed as the first model of permeable coverings material behaviour to provide a newer understanding of building materials and applications for the generation of new control procedures between the mechanical and electronic point of view of building construction materials.

A Translator for Converting CAD Models to Second Life

2010 ◽  
Author(s):  
Ratnadeep Paul ◽  
Sam Anand
Keyword(s):  
Virtual Worlds ◽  
Second Life ◽  
Product Life Cycle ◽  
Manufacturing Industry ◽  
Product Information ◽  
Life Cycle Management ◽  
3D Models ◽  
Transfer Product ◽  
Cad Models ◽  
Business Entities

Product Life-cycle Management (PLM) has been one of the single most important techniques to have been developed in the manufacturing industry. The increasing capabilities of internet and the ever increasing dependence of business entities on internet have led to the development of metaverses — internet-based 3D virtual worlds — which act as business platforms where companies display and showcase their latest products and services. This is in turn has led to a demand for development of methods for the easy transfer of data from stand alone PLM systems to the internet based virtual worlds. This paper presents the development of a translator which will transfer product data of 3D models created in CAD systems to an internet based virtual world. This translator uses a faceted-surface approach to transfer the product information. In this work CAD models were converted to a CAD-neutral data format, JT file format, and finally recreated in the metaverse Second Life (SL). Examples of models translated from JT to SL have been presented. A technique known as prim optimization, which increases the efficiency of the translation was also incorporated in the algorithm for the translator. Examples of prim optimization have been provided in the paper.

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.

scholarly journals Nonequispaced curvelet transform for seismic data reconstruction: A sparsity-promoting approach

Geophysics ◽  
2010 ◽  
Vol 75 (6) ◽  
pp. WB203-WB210 ◽  
Author(s):  
Gilles Hennenfent ◽  
Lloyd Fenelon ◽  
Felix J. Herrmann
Keyword(s):  
Seismic Data ◽  
First Generation ◽  
Second Generation ◽  
Synthetic Data ◽  
Curvelet Transform ◽  
Real Data ◽  
Sampled Data ◽  
Regularized Inversion ◽  
Irregularly Sampled Data ◽  
Fast Discrete Curvelet Transform

We extend our earlier work on the nonequispaced fast discrete curvelet transform (NFDCT) and introduce a second generation of the transform. This new generation differs from the previous one by the approach taken to compute accurate curvelet coefficients from irregularly sampled data. The first generation relies on accurate Fourier coefficients obtained by an [Formula: see text]-regularized inversion of the nonequispaced fast Fourier transform (FFT) whereas the second is based on a direct [Formula: see text]-regularized inversion of the operator that links curvelet coefficients to irregular data. Also, by construction the second generation NFDCT is lossless unlike the first generation NFDCT. This property is particularly attractive for processing irregularly sampled seismic data in the curvelet domain and bringing them back to their irregular record-ing locations with high fidelity. Secondly, we combine the second generation NFDCT with the standard fast discrete curvelet transform (FDCT) to form a new curvelet-based method, coined nonequispaced curvelet reconstruction with sparsity-promoting inversion (NCRSI) for the regularization and interpolation of irregularly sampled data. We demonstrate that for a pure regularization problem the reconstruction is very accurate. The signal-to-reconstruction error ratio in our example is above [Formula: see text]. We also conduct combined interpolation and regularization experiments. The reconstructions for synthetic data are accurate, particularly when the recording locations are optimally jittered. The reconstruction in our real data example shows amplitudes along the main wavefronts smoothly varying with limited acquisition imprint.

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