scholarly journals Simulating Expansion of the Intracranial Space to Accommodate Brain Swelling after Decompressive Craniectomy: Volumetric Quantification in a 3D CAD Skull Model with Contour Elevation

2021 ◽  
Vol 11 (4) ◽  
pp. 428
Author(s):  
Woon-Man Kung ◽  
Yao-Chin Wang ◽  
I-Shiang Tzeng ◽  
Yu-Te Chen ◽  
Muh-Shi Lin
Keyword(s):  
Decompressive Craniectomy ◽  
Statistical Significance ◽  
Three Dimensional ◽  
Computer Assisted ◽  
Skull Defect ◽  
3D Cad ◽  
Skull Model ◽  
Defect Area ◽  
Cad Models ◽  
Volumetric Quantification

Background: Decompressive craniectomy (DC) can be used to augment intracranial space and halt brainstem compromise. However, a widely adopted recommendation for optimal surgical extent of the DC procedure is lacking. In the current study, we utilized three-dimensional (3D) computer-assisted design (CAD) skull models with defect contour elevation for quantitative assessment. Methods: DC was performed for 15 consecutive patients, and 3D CAD models of defective skulls with contour elevations (0–50 mm) were reconstructed using commercial software. Quantitative assessments were conducted in these CAD subjects to analyze the effects of volumetric augmentation when elevating the length of the contour and the skull defect size. The final positive results were mathematically verified using a computerized system for numerical integration with the rectangle method. Results: Defect areas of the skull CAD models ranged from 55.7–168.8 cm2, with a mean of 132.3 ± 29.7 cm2. As the contour was elevated outward for 6 mm or above, statistical significance was detected in the volume and the volume-increasing rate, when compared to the results obtained from the regular CAD model. The volume and the volume-increasing rate increased by 3.665 cm3, 0.285% (p < 0.001) per 1 mm of contour elevation), and 0.034% (p < 0.001) per 1 cm2 of increase of defect area, respectively. Moreover, a 1 mm elevation of the contour in Groups 2 (defect area 125–150 cm2) and 3 (defect area >150 cm2, as a proxy for an extremely large skull defect) was shown to augment the volume and the volume-increasing rate by 1.553 cm3, 0.101% (p < 0.001) and 1.126 cm3, 0.072% (p < 0.001), respectively, when compared to those in Group 1 (defect area <125 cm2). The volumetric augmentation achieved by contour elevation for an extremely large skull defect was smaller than that achieved for a large skull defect. Conclusions: The 3D CAD skull model contour elevation method can be effectively used to simulate the extent of a space-occupying swollen brain and to quantitatively assess the extent of brainstem protection in terms of volume augmentation and volume-increasing rate following DC. As the tangential diameter (representing the degree of DC) exceeded the plateau value, volumetric augmentation was attenuated. However, an increasing volumetric augmentation was detected before the plateau value was reached.

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 Computational Design Framework for a Rapid Solid Freeform Fabrication Process

2000 ◽  
Author(s):  
Deepesh Khandelwal ◽  
T. Kesavadas
Keyword(s):  
Solid Freeform Fabrication ◽  
Optimization Technique ◽  
Three Dimensional ◽  
Computational Design ◽  
Freeform Fabrication ◽  
3D Cad ◽  
Build Time ◽  
Cad Models ◽  
Efficient Machine ◽  
Novel Concept

Abstract Solid Freeform Fabrication (SFF) techniques in recent years have shown tremendous promise in reducing the design time of products. This technique enables designers to get three-dimensional physical prototypes from 3D CAD models. Although SFF has gained popularity, the manufacturing time and cost have limited its use to small and medium sized parts. In this paper we have proposed a novel concept for rapidly building SFF parts by inserting prefabricated inserts into the fabricated part. A computational algorithm was developed for determining ideal placement of inserts/cores in the CAD model of the part being prototyped using a heuristic optimization technique called Simulated Annealing. This approach will also allow the designers to build multi-material prototypes using the Rapid Prototyping (RP) technique. By using cheaper pre-fabricates instead of costly photopolymers, the production cost of the SFFs can be reduced. Additionally it will also reduce build time, resulting in efficient machine utilization.

Measured Data Alignments for Monitoring Metal Additive Manufacturing Processes Using Laser Powder Bed Fusion Methods

2020 ◽  
Author(s):  
Shaw C. Feng ◽  
Yan Lu ◽  
Albert T. Jones
Keyword(s):  
Coordinate System ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Ex Situ ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Alignment Procedure ◽  
3D Cad ◽  
Data Alignment ◽  
Cad Models

Abstract The number and types of measurement devices used for monitoring and controlling Laser-Based Powder Bed Fusion of Metals (PBF-LB/M) processes and inspecting the resulting AM metal parts have increased rapidly in recent years. The variety of the data collected by such devices has increased, and the veracity of the data has decreased simultaneously. Each measurement device generates data in a unique coordinate system and in a unique data type. Data alignment, however, is required before 1) monitoring and controlling PBF-LB/M processes, 2) predicting the material properties of the final part, and 3) qualifying the resulting AM parts can be done. Aligned means all data must be transformed into a single coordinate system. In this paper, we describe a new, general data-alignment procedure and an example based on PBF-LB/M processes. The specific data objects used in this example include in-situ photogrammetry, thermography, ex-situ X-ray computed tomography (XCT), coordinate metrology, and computer-aided design (CAD) models. We propose a data-alignment procedure to align the data from melt pool images, scan paths, layer images, XCT three-dimensional (3D) model, coordinate measurements, and the 3D CAD model.

Triangular Mesh and Boundary Representation Combined Approach for 3D CAD Lightweight Representation for Collaborative Product Development

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Cong Hong Phong Nguyen ◽  
Young Choi
Keyword(s):  
Product Development ◽  
Computer Aided Design ◽  
Large Scale ◽  
Three Dimensional ◽  
Original Data ◽  
Triangular Mesh ◽  
Boundary Representation ◽  
Collaborative Product Development ◽  
3D Cad ◽  
Cad Models

The lightweight representation of three-dimensional computer-aided design (3D CAD) models has drawn much attention from researchers as its usefulness in collaborative product development is vast. Existing approaches are mostly based on feature depression or mesh-based simplification. In this article, a new approach for 3D CAD lightweight representation based on combining triangular mesh representation and boundary representation (B-rep) is proposed. The corresponding data structure as well as the conversion method from original data given in B-rep was developed. Considered as an essential application in collaborative product development, a case study on the visualization process of large-scale assembly models represented in the proposed lightweight representation was also conducted. The validation of the approach was performed via experiments with 3D CAD models in SAT format and by benchmarking with the conventional all-faceted approach with the same level of mesh resolution.

scholarly journals Investigation of Patient-Specific Maxillofacial Implant Prototype Development by Metal Fused Filament Fabrication (MF3) of Ti-6Al-4V

2021 ◽  
Vol 9 (10) ◽  
pp. 109
Author(s):  
Mohammad Qasim Shaikh ◽  
Subrata Deb Nath ◽  
Arulselvan Arumugam Akilan ◽  
Saleh Khanjar ◽  
Vamsi Krishna Balla ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Image Data ◽  
Total Porosity ◽  
Physical Models ◽  
Patient Specific ◽  
Fused Filament Fabrication ◽  
3D Cad ◽  
Prototype Development ◽  
Cad Models ◽  
First Time

Additive manufacturing (AM) and related digital technologies have enabled several advanced solutions in medicine and dentistry, in particular, the design and fabrication of patient-specific implants. In this study, the feasibility of metal fused filament fabrication (MF3) to manufacture patient-specific maxillofacial implants is investigated. Here, the design and fabrication of a maxillofacial implant prototype in Ti-6Al-4V using MF3 is reported for the first time. The cone-beam computed tomography (CBCT) image data of the patient’s oral anatomy was digitally processed to design a 3D CAD model of the hard tissue and fabricate a physical model by stereolithography (SLA). Using the digital and physical models, bone loss condition was analyzed, and a maxillofacial implant initial design was identified. Three-dimensional (3D) CAD models of the implant prototypes were designed that match the patient’s anatomy and dental implant requirement. In this preliminary stage, the CAD models of the prototypes were designed in a simplified form. MF3 printing of the prototypes was simulated to investigate potential deformation and residual stresses. The patient-specific implant prototypes were fabricated by MF3 printing followed by debinding and sintering using a support structure for the first time. MF3 printed green part dimensions fairly matched with simulation prediction. Sintered parts were characterized for surface integrity after cutting the support structures off. An overall 18 ± 2% shrinkage was observed in the sintered parts relative to the green parts. A relative density of 81 ± 4% indicated 19% total porosity including 11% open interconnected porosity in the sintered parts, which would favor bone healing and high osteointegration in the metallic implants. The surface roughness of Ra: 18 ± 5 µm and a Rockwell hardness of 6.5 ± 0.8 HRC were observed. The outcome of the work can be leveraged to further investigate the potential of MF3 to manufacture patient-specific custom implants out of Ti-6Al-4V.

scholarly journals STUDIES ON MASK-LESS ELECTROCHEMICAL ADDITIVE MANUFACTURING

2021 ◽  
Author(s):  
Abhishek Bhardwaj
Keyword(s):  
Additive Manufacturing ◽  
High Power ◽  
Room Temperature ◽  
Three Dimensional ◽  
High Impact ◽  
Layer By Layer ◽  
Metal Parts ◽  
3D Cad ◽  
Cad Models

<div>Added substance Manufacturing (AM) of metallic designs is a warm cycle of layer by layer metal added substance fabricating measure produces parts straightforwardly from 3D CAD models. In this assembling interaction confined electrochemical affidavit joins with the added substance producing technique to make metal parts at room temperature. In this paper, the attainability of Mask-less Electrochemical Additive Manufacturing (ECAM), as a non-warm interaction is considered. Layer by layer testimony has been finished utilizing the electrochemical tips to make nickel microstructures. All the while beat wave qualities and their impacts on affidavit have been considered. </div><div>Confined electrodeposition (LED) was investigated as an AM the interaction with high power over measure boundaries and yield boundaries. The confinement of electrodeposition is completed by utilizing Ultra microelectrodes (UME) and low tossing power electrolytes. Variety in some cycle boundaries, for example, voltage and terminal hole are found to have a high impact on yield boundaries like thickness. The reproductions can anticipate the yield width of affidavit of analyses with a blunder of 8- 30%, so it can possibly apply as an added substance-producing strategy of complex three-dimensional (3D) parts on the microscale.</div>

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.

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.

scholarly journals A New Car Concept Developed with Stylistic Design Engineering (SDE)

Inventions ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 30
Author(s):  
Giampiero Donnici ◽  
Leonardo Frizziero ◽  
Alfredo Liverani ◽  
Giulio Buscaroli ◽  
Luna Raimondo ◽  
...  
Keyword(s):  
Design Process ◽  
Computer Aided Design ◽  
Quality Function Deployment ◽  
Design Research ◽  
Design Method ◽  
Three Dimensional ◽  
Design Engineering ◽  
3D Cad ◽  
Cad Models ◽  
New City

In this work, a structured design method, the Stylistic Design Engineering (SDE), is applied for the construction of a new minivan car, in particular a new city car, which we will call FIAT 600 Omega. The SDE, or Stylistic Design Engineering, is a structured engineering method for carrying out automotive design projects. The SDE method consists of six different phases: (1) Analysis of stylistic trends; (2) Sketches; (3) 2D Computer Aided Design (CAD) drawings; (4) 3D CAD models; (5) Rendering; (6) Solid stylistic model (also called style maquette). This project deals with the external redesign of the Fiat 600 multiple, a small minivan which was very successful in the 1950s and 1960s. SDE is a methodology consisting of various technologies and design methodologies that will be further explained in detail, such as the Pininfarina method, the Quality Function Deployment (QFD) method, Benchmarking (BM), and Top Flop Analysis (TPA). The work was organized according to the different phases. Initially, the Fiat style was studied, in particular the style of the FIAT 600 MULTI PURPOUSE VEHICLE (MPV). This step is essential to better understand the characteristics of the brand and also the main characteristics carried out over the decades. Then we moved on to the freehand sketching phase, based on what we learned in the previous phase of the study. When a satisfactory shape was found for the new car, by analyzing and discarding the different proposals of the various types of style, we proceeded to the evaluation of the proportions and dimensions through two-dimensional drawings and finally we obtained the three-dimensional shape of the new car thanks to 3D CAD software and rendering software. Many advantages in the industrial world SDE takes together with its development. In fact, until the early 2000s, car design and styling was considered quite a craft activity, not a technical or scientific one, mostly based on the great capability of famous car designers and masters, just like Giugiaro, Zagato, Bertone, Pininfarina, Stephenson, Bangle, etc. Then, thanks to the industrial activity of Eng. Lorenzo Ramacciotti, former CEO of Pininfarina Spa and Mechanical Engineer, and also thanks to the academic studies developed at ALMA MATER STUDIORUM University of Bologna, SDE became the object of attention, because it is able to systematize the car design process and reduce costs. With SDE, a good design research or an industrial product development team can complete a car design project, also without the presence of a mentor. Car Design Process finally becomes with SDE a scientific method; Car Design becomes with SDE an industrial method. Industrial needs are nice products made in a short time; SDE is structured to attend these issues. Industrial challenges follow innovation, in shape and functionality; SDE is able to recognize innovation. Industrial benefits can be reached with SDE, ensuring beautiful aesthetic projects are realized systematically and with low costs.

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.

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