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.

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.

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.

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.

scholarly journals Feature-based translation of CAD models with macro-parametric approach: issues of feature mapping, persistent naming, and constraint translation

2020 ◽  
Vol 7 (5) ◽  
pp. 603-614 ◽  
Author(s):  
Mutahar Safdar ◽  
Tahir Abbas Jauhar ◽  
Youngki Kim ◽  
Hanra Lee ◽  
Chiho Noh ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Parametric Approach ◽  
Model Data ◽  
Feature Mapping ◽  
Product Model ◽  
Cad Systems ◽  
Cad System ◽  
Cad Models ◽  
Feature Based ◽  
Aided Design

Abstract Feature-based translation of computer-aided design (CAD) models allows designers to preserve the modeling history as a series of modeling operations. Modeling operations or features contain information that is required to modify CAD models to create different variants. Conventional formats, including the standard for the exchange of product model data or the initial graphics exchange specification, cannot preserve design intent and only geometric models can be exchanged. As a result, it is not possible to modify these models after their exchange. Macro-parametric approach (MPA) is a method for exchanging feature-based CAD models among heterogeneous CAD systems. TransCAD, a CAD system for inter-CAD translation, is based on this approach. Translators based on MPA were implemented and tested for exchange between two commercial CAD systems. The issues found during the test rallies are reported and analyzed in this work. MPA can be further extended to remaining features and constraints for exchange between commercial CAD systems.

Computation of Midsurface by Feature-Based Simplification–Abstraction–Decomposition

2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Yogesh H. Kulkarni ◽  
Anil Sahasrabudhe ◽  
Mukund Kale
Keyword(s):  
Computer Aided Design ◽  
Real Life ◽  
Boundary Representation ◽  
Manual Task ◽  
Computer Aided ◽  
Cad Models ◽  
Feature Based ◽  
Feature Information ◽  
Plastic Parts ◽  
Aided Design

Computer-aided design (CAD) models of thin-walled solids such as sheet metal or plastic parts are often reduced dimensionally to their corresponding midsurfaces for quicker and fairly accurate results of computer-aided engineering (CAE) analysis. Computation of the midsurface is still a time-consuming and mostly, a manual task due to lack of robust and automated techniques. Most of the existing techniques work on the final shape (typically in the form of boundary representation, B-rep). Complex B-reps make it hard to detect subshapes for which the midsurface patches are computed and joined, forcing usage of hard-coded heuristic rules, developed on a case-by-case basis. Midsurface failures manifest in the form of gaps, overlaps, nonmimicking input model, etc., which can take hours or even days to correct. The research presented here proposes to address these problems by leveraging feature-information available in the modern CAD models, and by effectively using techniques like simplification, abstraction, and decomposition. In the proposed approach, first, the irrelevant features are identified and removed from the input FbCAD model to compute its simplified gross shape. Remaining features then undergo abstraction to transform into their corresponding generic Loft-equivalents, each having a profile and a guide curve. The model is then decomposed into cellular bodies and a graph is populated, with cellular bodies at the nodes and fully overlapping-surface-interfaces at the edges. The nodes are classified into midsurface-patch generating nodes (called “solid cells” or sCells) and interaction-resolving nodes (“interface cells” or iCells). In a sCell, a midsurface patch is generated either by offset or by sweeping the midcurve of the owner-Loft-feature's profile along with its guide curve. Midsurface patches are then connected in the iCells in a generic manner, thus resulting in a well-connected midsurface with minimum failures. Output midsurface is then validated topologically for correctness. At the end of this paper, real-life parts are used to demonstrate the efficacy of the proposed approach.

Interpreting Three-Dimensional Shape Distributions

2005 ◽  
Vol 219 (6) ◽  
pp. 553-566 ◽  
Author(s):  
H J Rea ◽  
R Sung ◽  
J R Corney ◽  
D E R Clark ◽  
N K Taylor
Keyword(s):  
Computer Aided Design ◽  
Shape Function ◽  
Three Dimensional ◽  
Shape Functions ◽  
Three Dimensional Model ◽  
Retrieval Systems ◽  
Cad Models ◽  
Dimensional Shape ◽  
Complex Engineering ◽  
Aided Design

Effective content-based shape retrieval systems would allow engineers to search databases of three-dimensional computer-aided design (CAD) models for objects with specific geometries or features. Much of the academic work in this area has focused on the development of indexing schemes based on different types of three-dimensional to two-dimensional ‘shape functions’. Ideally, the shape function used to generate a distribution should be easy to compute and permit the discrimination of both large and small features. The work reported in this paper describes the properties of three new shape distributions based on computationally simple shape functions. The first shape function calculates the arithmetic difference between distributions derived (using the original D2 distance shape function) from both a three-dimensional model and its convex hull. The second shape function is obtained by sampling the angle between random pairs of facets on the object. The third shape function uses the surface orientation to filter the results of a distance distribution. The results reported in this paper suggest that these novel shape functions improve significantly the ability of shape distributions to discriminate between complex engineering parts.

scholarly journals Application of process mapping for digitization of mechanical parts with 3D laser scanner

2018 ◽  
Vol 9 ◽  
pp. 11 ◽  
Author(s):  
Antonio Piratelli-Filho ◽  
Alberto José Alvares ◽  
Rosenda Valdés Arencibia
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Mapping Method ◽  
Free Form ◽  
Process Mapping ◽  
Mechanical Parts ◽  
Cad Models ◽  
Measurement Planning ◽  
Aided Design

This work presents a systematization method for digitization of mechanical parts with three-dimensional (3D) laser scanner using the process mapping method. The application involves the use of the IDEFØ methodology of process mapping to address the sequence of steps required to obtain the computer-aided design (CAD) model of the measured part. The variables involved in the setup and measurement with 3D laser scanner were investigated and applied to regular and free-form parts, and the parameter geometry, texture, light reflection and procedure of data acquisition were considered in the analysis. The software commands used to create the CAD models were also included and the ones related to mesh and surface creation were detailed. The systematized measurement planning was graphi graphically presented, and it proved useful to operators during the digitization process.

A Framework for Explicating Formal Geometrical and Dimensional Tolerances Schema From Manufacturing Process Plans for Three-Dimensional Conformance Analysis

2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Payam Haghighi ◽  
Prashant Mohan ◽  
Jami J. Shah ◽  
Joseph K. Davidson
Keyword(s):  
Computer Aided Design ◽  
Reference Frames ◽  
Three Dimensional ◽  
Machining Process ◽  
Design Specification ◽  
Math Model ◽  
Process Plans ◽  
Cad Models ◽  
Dimensional Conformance ◽  
Aided Design

A process plan is an instruction set for the manufacture of parts generated from detailed design drawings or computer-aided design (CAD) models. While these plans are highly detailed about machines, tools, fixtures, and operation parameters, tolerances typically show up in less formal manner, if at all. It is not uncommon to see only dimensional plus/minus values on rough sketches accompanying the instructions. On the other hand, design drawings use standard geometrical and dimensional tolerances (GD&T) symbols with datums and datum reference frames (DRFs) clearly specified. This is not to say that process planners do not consider tolerances; they are implied by way of choices of fixtures, tools, machines, and operations. Process planners do tolerance charting in converting design tolerances to the manufacturing datum flow based on operation sequence, but the resulting plans cannot be audited for conformance to design specification. In this paper, we present a framework for explicating the GD&T schema implied by machining process plans. The first step is to derive DRFs from the fixturing method in each setup. Then, basic dimensions for features machined in the setup are determined with respect to the extracted DRF. Using shop data for the machines and operations involved, the range of possible geometric variations are estimated for each type (form, size, orientation, and position). The sequence of operations determines the datum flow chain. Once we have a formal manufacturing GD&T schema, we can analyze and compare it to design specification using the T-map math model.

Profiling the Desirable CAD Trainee: Technical Background, Personality Attributes, and Learning Preferences

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Ramsey F. Hamade
Keyword(s):  
Learning Styles ◽  
Learning Style ◽  
Computer Aided Design ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Learning Preferences ◽  
Actual Behavior ◽  
3D Cad ◽  
Active Sensor ◽  
Cad Models

This research aims to explore some of the underlying reasoning for why some individuals acquire mechanical computer-aided design (CAD) skills with relative ease while some others seem to falter. A methodical study was performed by monitoring 74 mechanical engineering seniors (over a 3 year period) in a semester-long formal training on a commercial three-dimensional (3D) CAD package (PRO/ENGINEER, version WILDFIRE). The study methodically explored the trainees’ (1) technical background, (2) personality attributes, and (3) learning preferences. Investigating the technical background included quantifying the trainees’ following technical foundations: basic math, advanced math, CAD-related math, computer science and engineering, methodologies related to CAD, graphics, and mechanical design. Determining the trainees’ personality attributes included exploring their willingness-to-learn CAD, perception, gauging their actual behavior (practice), and CAD syntax learned throughout the training. Trainees’ learning preferences were determined according to the index of learning styles (ILS). Furthermore, and in order to assess the trainees’ progress in CAD knowledge acquisition, competency tests were conducted at four intervals throughout the semester-long study. The assessment involved hands-on modeling of CAD test parts of comparable complexity. At the conclusion of the study, statistical methods were used to correlate the trainees’ attributes with their monitored performance. Only a fraction (17 out of a class of 74 trainees or 1 in 4) of the trainees were found to fit the “star CAD trainee” mold, which is defined here as someone who is fast on the tube and perceptive enough to see through the procedure of building progressively more sophisticated CAD models. A profile of the star CAD trainee character emerges as an individual who is technically competent, perceptive, and motivated. The study also reveals these most desirable trainees to possess an active, sensor, visual, and sequential learning style.

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