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.

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.

Concept of an Automatic Integration of Parts Measurement Data Into Feature-Based CAD Models

2018 ◽  
Author(s):  
Thiago Weber Martins ◽  
Lars Niemczik ◽  
Reiner Anderl
Keyword(s):  
Measurement Data ◽  
Product Development Process ◽  
Work Piece ◽  
Cad Model ◽  
3D Cad ◽  
Cad System ◽  
Target Values ◽  
Cad Models ◽  
Feature Based ◽  
Sheet Metal Profiles

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.

On the Development of Blend Faces and Holes Recognition Algorithm for CAE Applications

2015 ◽  
Vol 656-657 ◽  
pp. 789-794 ◽  
Author(s):  
Jiing Yih Lai ◽  
Zi Wei You ◽  
Yu Kai Chiu ◽  
Ming Hsuan Wang ◽  
Chia Hsiang Hsu ◽  
...  
Keyword(s):  
Finite Element ◽  
Mesh Generation ◽  
Computational Efficiency ◽  
Recognition Algorithm ◽  
Cad Model ◽  
Key Factors ◽  
Factors Affecting ◽  
3D Cad ◽  
Cad Models

Mesh generation is one of the key factors affecting computational efficiency and accuracy in finite element analysis.More and more software provides modules for automatic meshes generation. Owing to the complexity and variety of the shape on a CAD model, it needs the recognition of specific features to enhance the success of meshes generation. Holes are one of the fundamental features in 3D CAD models and appear in various types of form. The aim of this study is to present a method for the recognition of different kinds of holes. The primary concept of the proposed algorithm is to detect blend faces first, and then search for holes in accordance with the loop data in the B-rep model. The procedures for the recognition of blend faces and holes are described. Several examples are also presented to demonstrate the feasibility of the proposed algorithm.

3D CAD Model Retrieval Algorithm Based on Accessibility Cone Distributions

2013 ◽  
Vol 834-836 ◽  
pp. 1444-1447
Author(s):  
Wei Qiang
Keyword(s):  
Engineering Application ◽  
Similarity Coefficient ◽  
Retrieval Algorithm ◽  
Cad Model ◽  
3D Cad ◽  
Planar Grid ◽  
Model Retrieval ◽  
Cad Models ◽  
The Given ◽  
3D Cad Model Retrieval

To reuse 3D CAD models more efficiently, a new 3D CAD model retrieval algorithm based on accessibility cone distributions is proposed. Firstly, a sufficiently large number of random sample points on surface of 3D CAD model are taken and the normal direction of each sample point is recorded. Then, the accessibility cone of the given sampled point is computed. Secondly, a planar grid is constructed to express the accessibility cone distribution by obtaining a statistic data of the sampled points. Lastly, the L1 distance metric method is taken to compute the similarity between the two accessibility cone matrices, which can give the similarity coefficient for two compared 3D CAD models. Experiments results show that the algorithm can effectively support 3D CAD model retrieval, and the efficiency meets the requirement of engineering application.

Bag-of-Features Sampling Techniques for 3D CAD Model Retrieval

2011 ◽  
Author(s):  
Y. Wang ◽  
W. F. Lu ◽  
J. Y. H. Fuh ◽  
Y. S. Wong
Keyword(s):  
Feature Detection ◽  
Sampling Techniques ◽  
Cad Model ◽  
Sampling Strategies ◽  
3D Cad ◽  
Bag Of Features ◽  
Model Retrieval ◽  
Cad Models ◽  
Dense Sampling ◽  
3D Cad Model Retrieval

This paper investigates two sampling strategies, dense sampling and PHOW sampling, for bag-of-features 3D CAD model retrieval. Previous methods [1] use original salient SIFT feature detection for general 3D model retrieval which does not suit the need for CAD models representation. CAD models contain mostly piecewise-smooth surfaces and thus only sharp edges can be described. To overcome these limitations, two new sampling strategies are investigated to improve the feature extraction process. Dense sampling extracts SIFT features on regular spatial grids with even spacing. Pyramid Histogram Of visual Words (PHOW) [2] extracts features on repeatedly finer scales. Both the two sampling methods extract features that are covered the whole shape. In addition, the influences of codebook size and distance metric are also studied to optimize the retrieval performance. Experiments on Purdue Engineering Benchmark [3] show that the proposed sampling techniques achieve better retrieval accuracy than the original salient SIFT sampling method.

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.

Evaluation of CAD Model Manipulation in Desktop and Multimodal Immersive Interface

2013 ◽  
Vol 325-326 ◽  
pp. 289-293
Author(s):  
Florin Gîrbacia
Keyword(s):  
Evaluation Study ◽  
Direct Access ◽  
Cad Model ◽  
Multimodal Interface ◽  
Space Model ◽  
3D Cad ◽  
3D Objects ◽  
Software Interface ◽  
Cad Models ◽  
Tracking Device

In this paper is presented an evaluation study regarding the manipulation of 3D CAD models using multimodal Virtual Reality (VR) interface and traditional desktop environment. A multimodal interface based on VR technologies that offers direct access to the space model by using several sensorial channels (visual, tactile, verbal) is described. Users can manipulate 3D objects using 6DOF tracking device, gestures and visualize the design status in an immersive CAVE - like system. The results of the evaluation study illustrate that using VR technologies as an alternative to replace WIMP CAD software interface is viable and brings more advantages.

Identifying Common Platform Shape for a Family of Components

2004 ◽  
Author(s):  
Manojkumar Natarajan ◽  
Zahed Siddique
Keyword(s):  
Three Dimensional ◽  
Product Platforms ◽  
3D Cad ◽  
Solid Models ◽  
Design Attributes ◽  
Design Cycle ◽  
Cad Models ◽  
Dimensional Shape ◽  
Three Dimensional Shape ◽  
Common Platform

To survive in today’s volatile and changing markets, companies are now faced with the problem of providing more customization, greater quality, faster response, more innovative designs and lower prices. New models need to be introduced in the market more frequently, which has given momentum to design product platforms. Use of common components can reduce the design and manufacturing time significantly. Determining commonality among different components is a key to reducing the new product design cycle time. CAD files can be used as a means to measure commonality for a set of similar components. This paper presents a tree-based approach to compare a set of similar 3D CAD models, measure shape commonality and identify the common platform shape. First a mapping of the solid models using the IGES format to IPG (IGES Parametric Graph) has been developed. The IPG, a Labeled Attribute Tree, is used to capture the three dimensional shape and design attributes along with the function of the component. The IPGs are then used to obtain a commonality index and establish a common platform for a set of similar products. The applicability of the method is demonstrated using CAD models of a family of casing. This research can also be applied to identify existing components that can be reused in new products.

3D CAD Model Similarity Assessment and Retrieval Using DBS

2005 ◽  
Author(s):  
Wei Gao ◽  
Shuming Gao ◽  
Yusheng Liu
Keyword(s):  
Preliminary Test ◽  
Cad Model ◽  
Test Results ◽  
Huge Amount ◽  
Geometric Information ◽  
New Approach ◽  
Similarity Assessment ◽  
3D Cad ◽  
Cad Models ◽  
Model Similarity

Similarity assessment and retrieval of 3D CAD models play a key role in achieving reuse of huge amount of 3D CAD models. In this paper, a new approach to similarity assessment and retrieval of 3D CAD models based on dilation based skeleton (DBS) is presented. First the DBS of a 3D CAD model is introduced; Then the detailed algorithms of generating and refining the DBS of a 3D CAD model are described; Furthermore the method of performing similarity assessment and retrieval of 3D CAD models based on the matching of the DBS graphs derived from the DBS representations and containing both primary topological and geometric information of the models is presented; Finally some preliminary test results are given.

Partial Matching of 3D CAD Models with Attributed Graph

2014 ◽  
Vol 528 ◽  
pp. 302-309
Author(s):  
Hong Shen Wang ◽  
Lin Zhang ◽  
Yong Gui Zhang
Keyword(s):  
Target Object ◽  
Similarity Coefficient ◽  
Boundary Representation ◽  
Cad Model ◽  
Matching Algorithm ◽  
3D Cad ◽  
Matching Process ◽  
Attributed Graph ◽  
Attributed Graphs ◽  
Cad Models

This paper presents an algorithm for matching similar sub-parts of 3D CAD models. The matching process is based on the attributed graphs. Each model in target object database is represented by attributed graph. The sub-part, which is to be retrieved, is selected interactively by users from a 3D CAD model described by boundary representation (B-Rep) and its attributed graph is automatically generated. For each target CAD model in the database, its surfaces which are similar to those surfaces of the query sub-part are identified by means of the attributes. Then, other irrelevant surfaces of the target object are deleted from the model’s attributed graph. Thus, the parts that are possibly similar to the query sub-part are separated from the target model. A method for calculating the similarity coefficient between the separated part and the sub-part, which uses an optimal matching algorithm for bi-graphs, is proposed. Experimental results show that this algorithm can efficiently achieve partial retrieval.

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