scholarly journals Reconfigurable 3D CAD Feature Recognition Supporting Confluent n-Dimensional Topologies and Geometric Filters for Prismatic and Curved Models

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1356
Author(s):  
Juan Pareja-Corcho ◽  
Oscar Betancur-Acosta ◽  
Jorge Posada ◽  
Antonio Tammaro ◽  
Oscar Ruiz-Salguero ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Feature Recognition ◽  
Graph Isomorphism ◽  
Search Space ◽  
Test Sequence ◽  
3D Cad ◽  
Cad Models ◽  
Aided Design ◽  
Future Work ◽  
Order Sequence

Feature Recognition (FR) in Computer-aided Design (CAD) models is central for Design and Manufacturing. FR is a problem whose computational burden is intractable (NP-hard), given that its underlying task is the detection of graph isomorphism. Until now, compromises have been reached by only using FACE-based geometric information of prismatic CAD models to prune the search domain. Responding to such shortcomings, this manuscript presents an interactive FR method that more aggressively prunes the search space with reconfigurable geometric tests. Unlike previous approaches, our reconfigurable FR addresses curved EDGEs and FACEs. This reconfigurable approach allows enforcing arbitrary confluent topologic and geometric filters, thus handling an expanded scope. The test sequence is itself a graph (i.e., not a linear or total-order sequence). Unlike the existing methods that are FACE-based, the present one permits combinations of topologies whose dimensions are two (SHELL or FACE), one (LOOP or EDGE), or 0 (VERTEX). This system has been implemented in an industrial environment, using icon graphs for the interactive rule configuration. The industrial instancing allows industry based customization and itis faster when compared to topology-based feature recognition. Future work is required in improving the robustness of search conditions, treating the problem of interacting or nested features, and improving the graphic input interface.

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.

Partial Matching Algorithm of 3D CAD Models Based on the Constraints of Transition Features

2010 ◽  
Vol 97-101 ◽  
pp. 3371-3375
Author(s):  
Kai Xing Zhang ◽  
Shu Sheng Zhang ◽  
Xiao Liang Bai
Keyword(s):  
Feature Recognition ◽  
Graph Isomorphism ◽  
Topological Information ◽  
Machining Features ◽  
New Approach ◽  
Partial Matching ◽  
Mechanical Parts ◽  
3D Cad ◽  
Matching Efficiency ◽  
Cad Models

The CAD models of mechanical parts usually have many blends and chamfers, and the existence of these machining features can greatly change the geometric and topological patterns of the CAD models, but the existing partial matching algorithms cannot match the CAD models which contain machining features such as blends and chamfers. In this paper, a new approach to partial matching based on the constraints of transition features is proposed. Firstly, the transition features are identified by feature recognition, and then these machining features are removed to eliminate the impacts to the geometric and topological information of the CAD models, and the attribute adjacent graph is reconstructed, finally, the sub-graph isomorphism approach is used to achieve the partial matching. Experimental results show that this method can achieve partial matching of CAD models which contain machining features such as blends and chamfers, and the matching efficiency can satisfy the requirement of the engineering retrieval.

Associating 2D Sketch Information with 3D CAD Models for VR/AR Viewing During Bridge Maintenance Process

2019 ◽  
Vol 13 (4) ◽  
pp. 482-489 ◽  
Author(s):  
Fumiki Tanaka ◽  
Makoto Tsuchida ◽  
Masahiko Onosato ◽  
◽  
Keyword(s):  
Computer Aided Design ◽  
Mixed Reality ◽  
Industry Foundation Classes ◽  
3D Cad ◽  
Inspection Process ◽  
Cad Models ◽  
Maintenance And Inspection ◽  
Inspection Data ◽  
Aided Design ◽  
2D Sketches

Virtual reality (VR), augmented reality (AR), and mixed reality technologies are utilized at various stages of product lifecycle. For products with long lifecycles such as bridges and dams, the maintenance and inspection stages are very important to keep the product safe and well-functioning. One of the advantages of VR/AR is the ability to add important information such as past inspection data. Past inspection information is summarized in a document consisting of the 2D sketches of bridge degradation drawings. However, this degradation sketch is in 2D, and it has no correspondence with the 3D world. In this study, we propose a method to associate important information of 2D sketches with a 3D industry foundation classes (IFC) model, which is a standardized computer aided design model. To display a VR image of a bridge during the inspection process, the proposed method is applied to the 3D IFC model of the bridge and 2D degradation sketch of the inspection report.

Shape Comparison of 3D Models Based on Features and Parameters

2008 ◽  
Author(s):  
Karthik Viswanathan ◽  
Sagar Chowdhury ◽  
Zahed Siddique
Keyword(s):  
Computer Aided Design ◽  
Product Family ◽  
3D Models ◽  
3D Cad ◽  
Solid Models ◽  
Cad Models ◽  
3D Solid ◽  
Aided Design ◽  
Distinct Features ◽  
Common Platform

Computer-Aided Design (CAD) is used extensively during mechanical product design, which involves creating 3D models of components and then assembling them into modules and systems. Methods and tools to compare components and identify a common platform using these 3D CAD models of components would facilitate faster specification of product family architecture. Hence, there is a need to develop means for comparing component geometry, in order to identify the common and distinct features, determine component commonality, and identify a common platform for the set of components. This paper presents an approach to determine geometric commonality between components from their 3D solid models. The approach consists of performing a pair-wise comparison between components. To measure commonality for a pair of components, first all feature-pair’s dimensions and positions are measured, which then combined to give the overall component-pair commonality.

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.

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.

Intuitive 3D Computer-Aided Design (CAD) System With Multimodal Interfaces

2013 ◽  
Author(s):  
V. G. Nanjundaswamy ◽  
Amit Kulkarni ◽  
Zhuo Chen ◽  
Prakhar Jaiswal ◽  
Sree Shankar S. ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Brain Computer Interface ◽  
3D Models ◽  
Multimodal Interfaces ◽  
Computer Interface ◽  
Cad Modeling ◽  
3D Cad ◽  
Cad System ◽  
Cad Models ◽  
Aided Design

The existing interfaces for 3D CAD modeling softwares use 2D subspace inputs such as x and y axes of mouse to create 3D models. These existing interfaces are inherently modal because one needs to switch between subspaces, and disconnects the input space from modeling space. This makes existing interfaces tedious, complex, non-intuitive and difficult to learn. In this paper, a multi-sensory, interactive, and intuitive 3D CAD modeling interface is presented to address these shortcomings. Three different modalities (gestures, brain-computer interface, and speech) have been used for creating interactive and intuitive 3D CAD modeling interface. DepthSense® camera from SoftKinetic is used to recognize gestures, EEG Neuro-headset from Emotiv® is used for acquiring, and processing neuro-signals and CMU Sphinx is used for recognizing and processing speech. Multiple CAD models created by several users using the proposed multi-modal interface are presented. In conclusion, the proposed system is easier to learn and use as compared to the already existing systems.

MVCNN++: Computer-Aided Design Model Shape Classification and Retrieval Using Multi-View Convolutional Neural Networks

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Atin Angrish ◽  
Akshay Bharadwaj ◽  
Binil Starly
Keyword(s):  
Neural Networks ◽  
Computer Aided Design ◽  
Training Data ◽  
Shape Classification ◽  
Training Time ◽  
3D Cad ◽  
Computer Aided ◽  
Cad Models ◽  
Engineering Models ◽  
Aided Design

Abstract Deep neural networks (DNNs) have been successful in classification and retrieval tasks of images and text, as well as in the graphics domain. However, these DNNs algorithms do not translate to 3D engineering models used in the product design and manufacturing. This paper studies the use of multi-view convolutional neural network (MVCNN) algorithm enhanced by the addition of engineering metadata, for classification and retrieval of 3D computer-aided design (CAD) models. The proposed algorithm (MVCNN++) builds on the MVCNN algorithm with the addition of part dimension data, improving its efficacy for manufacturing part classification and yielding an improvement in classification accuracy of 5.8% over the original version. Unlike datasets used for 3D shape classification and retrieval in the computer graphics domain, engineering level description of 3D CAD models do not yield themselves to neat, distinct classes. Techniques such as relaxed-classification and prime angled cameras for capturing feature detail were used to address training data capture issues specific to 3D CAD models, along with the use of transfer learning to reduce training time. Our study has shown that DNNs can be used to search and discover relevant 3D engineering models in large public repositories, making 3D models accessible to the community.

AUTOMATIC RECONSTRUCTION OF 3D CAD MODELS FROM DIGITAL SCANS

1999 ◽  
Vol 09 (04n05) ◽  
pp. 327-369 ◽  
Author(s):  
FAUSTO BERNARDINI ◽  
CHANDRAJIT L. BAJAJ ◽  
JINDONG CHEN ◽  
DANIEL R. SCHIKORE
Keyword(s):  
Computer Aided Design ◽  
Triangle Mesh ◽  
Modeling And Analysis ◽  
Object A ◽  
3D Cad ◽  
Surface Patches ◽  
Alpha Shapes ◽  
Cad Models ◽  
Fully Automatic ◽  
Aided Design

We present an approach for the reconstruction and approximation of 3D CAD models from an unorganized collection of points. Applications include rapid reverse engineering of existing objects for use in a virtual prototyping environment, including computer aided design and manufacturing. Our reconstruction approach is flexible enough to permit interpolation of both smooth surfaces and sharp features, while placing few restrictions on the geometry or topology of the object. Our algorithm is based on alpha-shapes to compute an initial triangle mesh approximating the surface of the object. A mesh reduction technique is applied to the dense triangle mesh to build a simplified approximation, while retaining important topological and geometric characteristics of the model. The reduced mesh is interpolated with piecewise algebraic surface patches which approximate the original points. The process is fully automatic, and the reconstruction is guaranteed to be homeomorphic and error bounded with respect to the original model when certain sampling requirements are satisfied. The resulting model is suitable for typical CAD modeling and analysis applications.

scholarly journals An isogeometric b-rep mortar-based mapping method for non-matching grids in fluid-structure interaction

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Andreas Apostolatos ◽  
Altuğ Emiroğlu ◽  
Shahrokh Shayegan ◽  
Fabien Péan ◽  
Kai-Uwe Bletzinger ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Fluid Structure Interaction ◽  
Mapping Method ◽  
Boundary Representation ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Discrete Surface ◽  
Cad Models ◽  
Volume Method ◽  
Aided Design

AbstractIn this study the isogeometric B-Rep mortar-based mapping method for geometry models stemming directly from Computer-Aided Design (CAD) is systematically augmented and applied to partitioned Fluid-Structure Interaction (FSI) simulations. Thus, the newly proposed methodology is applied to geometries described by their Boundary Representation (B-Rep) in terms of trimmed multipatch Non-Uniform Rational B-Spline (NURBS) discretizations as standard in modern CAD. The proposed isogeometric B-Rep mortar-based mapping method is herein extended for the transformation of fields between a B-Rep model and a low order discrete surface representation of the geometry which typically results when the Finite Volume Method (FVM) or the Finite Element Method (FEM) are employed. This enables the transformation of such fields as tractions and displacements along the FSI interface when Isogeometric B-Rep Analysis (IBRA) is used for the structural discretization and the FVM is used for the fluid discretization. The latter allows for diverse discretization schemes between the structural and the fluid Boundary Value Problem (BVP), taking into consideration the special properties of each BVP separately while the constraints along the FSI interface are satisfied in an iterative manner within partitioned FSI. The proposed methodology can be exploited in FSI problems with an IBRA structural discretization or to FSI problems with a standard FEM structural discretization in the frame of the Exact Coupling Layer (ECL) where the interface fields are smoothed using the underlying B-Rep parametrization, thus taking advantage of the smoothness that the NURBS basis functions offer. All new developments are systematically investigated and demonstrated by FSI problems with lightweight structures whereby the underlying geometric parametrizations are directly taken from real-world CAD models, thus extending IBRA into coupled problems of the FSI type.

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