Conventional Computer-aided Design Research Articles

Comparison of the Efficacy of Artificial Intelligence-Powered Software in Crown Design: An In Vitro Study

Introduction and aimsArtificial intelligence (AI) has been adopted in the field of dental restoration. This study aimed to evaluate the time efficiency and morphological accuracy of crowns designed by two AI-powered software programs in comparison with conventional computer-aided design software. MethodsA total of 33 clinically adapted posterior crowns were involved in the standard group. AI Automate (AA) and AI Dentbird Crown (AD) used two AI-powered design software programs, while the computer-aided experienced and computer-aided novice employed the Exocad DentalCAD software. Time efficiency between the AI-powered groups and computer-aided groups was evaluated by assessing the elapsed time. Morphological accuracy was assessed by means of three-dimensional geometric calculations, with the root-mean-square error compared against the standard group. Statistical analysis was conducted via the Kruskal–Wallis test (α = 0.05). ResultsThe time efficiency of the AI-powered groups was significantly higher than that of the computer-aided groups (P < .01). Moreover, the working time for both AA and AD groups was only one-quarter of that for the computer-aided novice group. Four groups significantly differed in morphological accuracy for occlusal and distal surfaces (P < .05). The AD group performed lower accuracy than the other three groups on the occlusal surfaces (P < .001) and the computer-aided experienced group was superior to the AA group in terms of accuracy on the distal surfaces (P = .029). However, morphological accuracy showed no significant difference among the four groups for mesial surfaces and margin lines (P > .05). ConclusionAI-powered software enhanced the efficiency of crown design but failed to excel at morphological accuracy compared with experienced technicians using computer-aided software. AI-powered software requires further research and extensive deep learning to improve the morphological accuracy and stability of the crown design.

An AIGC-empowered methodology to product color matching design

With the emergence of various generative AI applications, artificial intelligence-generated content (AIGC) demonstrates positive potential for design activities. However, few scholars have proposed a practical AIGC-based design methodology. This paper introduces an AIGC-empowered methodology for product color-matching design. ChatGPT generates target imageries describing the design features, and Midjourney constructs a shape sample database based on these imageries, identifying representative shapes through consumer perceptual questionnaires. Meanwhile, three Midjourney-based color image generation methods are proposed to generate color images that match the target imageries, and an application is developed to extract the dominant colors from these images. Finally, based on the color harmony theory, the optimal color combinations are derived from the extracted dominant colors and applied to the representative shape to generate color-matching alternatives. AHP-based expert evaluation (Evaluation_1) and consumer perceptual evaluation (Evaluation_2) are employed to ascertain the optimal design solution. This paper uses the household vacuum cleaner as an example to demonstrate the proposed color-matching methodology. Consistent evaluation results are obtained, supported by a significant Pearson correlation coefficient. Research findings suggest that AIGC has the potential to revolutionize traditional product color-matching design. Additionally, the methodology highlights the collaborative potential between generative AIs and conventional computer-aided design tools.

Advanced lung tumor diagnosis using a 3D deep neural network based CAD system

In the realm of interdisciplinary research, Computer-Aided Diagnosis (CAD) emerges as a pivotal tool, aiding radiologists in comprehending lung computer tomography scans (both 2D and 3D) for enhanced prediction of lung malignancy and benign cases with heightened accuracy. The objective of clinical examination is to furnish medical experts with more effective scientific insights and treatment strategies. As conventional computer-aided design frameworks prove to be increasingly challenging and time-consuming, this study delves into the contemporary landscape of clinical image analysis in computer-aided diagnosis, with a specific focus on the architecture of the Convolutional Neural Network (CNN). Employing the Kaggle Data Science Bowl dataset, encompassing CT scan images of lung tumors, our proposed CNN architecture has exhibited remarkable performance. Notably, the CNN Net deep learning algorithm achieved a peak classification accuracy of 94%, coupled with a substantial sensitivity and specificity of 90.2%. The extensive 15-fold cross-validation procedure further highlighted the robustness of the CNN network, reporting a minimal log loss of 0.54. This outcome underscores the superior diagnostic capabilities of the CNN architecture in the context of lung tumor diagnosis. In essence, this paper not only contributes to advancements in radio diagnosis and precision medication but also provides a valuable addition to the field by presenting a meticulous figure for computer-aided design utilization.

3D printed patient-specific fixation plates for the treatment of slipped capital femoral epiphysis: Topology optimization vs. conventional design

Orthopedic plates are commonly used after osteotomies for temporary fixation of bones. Patient-specific plates have recently emerged as a promising fixation device. However, it is unclear how various strategies used for the design of such plates perform in comparison with each other. Here, we compare the biomechanical performance of 3D printed patient-specific bone plates designed using conventional computer-aided design (CAD) techniques with those designed with the help of topology optimization (TO) algorithms, focusing on cases involving slipped capital femoral epiphysis (SCFE). We established a biomechanical testing protocol to experimentally assess the performance of the designed plates while measuring the full-field strain using digital image correlation. We also created an experimentally validated finite element model to analyze the performance of the plates under physiologically relevant loading conditions. The results indicated that the TO construct exhibited higher ultimate load and biomechanical performance as compared to the CAD construct, suggesting that TO is a viable approach for the design of such patient-specific bone plates. The TO plate also distributed stress more evenly over the screws, likely resulting in more durable constructs and improved anatomical conformity while reducing the risk of screw and plate failure during cyclic loading. Although differences existed between finite element analysis and experimental testing, this study demonstrated that finite element modelling can be used as a reliable method for evaluating and optimizing plates for SCFE patients. In addition to enhancing the mechanical performance of patient-specific fixation plates, the utilization of TO in plate design may also improve the surgical outcome and decrease the recovery time by reducing the plate and incision sizes.

Precise channel temperature prediction in AlGaN/GaN HEMTs via closed-form empirical expression

In this study, we introduced a closed-form empirical expression for estimating the channel temperature in AlGaN/GaN HEMTs. This model incorporates parameters such as substrate thickness, gate length, gate width, and temperature-dependent thermal conductivity. The model's validity was rigorously established through comprehensive comparisons involving the channel temperature measurement procedure (DC) and TCAD device simulations. The outcomes exhibited a noteworthy alignment with the observed model data, reinforcing its credibility. The model yields a notably improved accuracy in channel temperature estimation compared to assumptions based on constant thermal conductivity. This observation holds particular significance for GaN/Sapphire HEMTs. The utilization of the closed-form expression enables the simultaneous optimization of both electrical and thermal properties, utilizing conventional computer-aided design tools.

Direct point-cloud-based numerical analysis using octree meshes

Point-cloud-based geometry acquisition techniques have seen an increased deployment in recent years and can be used in many branches of science and engineering. Different from conventional computer aided design (CAD) models, point-cloud data can be directly obtained by applying surveying technology, such as laser scanning devices. This opens a pathway to an efficient and highly automatic acquisition of the geometric model. However, in order to perform numerical analysis on point-cloud models using conventional finite element approaches, a surface reconstruction is required, which is both time consuming and error-prone. Therefore, a direct numerical analysis framework based on point-cloud data in conjunction with polyhedral element techniques is developed in this contribution. To this end, a robust and efficient meshing paradigm based on the direct use of point-cloud data (without surface reconstruction) is proposed. From the geometric model, a trimmed octree mesh containing only a limited number of master elements (element patterns) is directly generated, which is highly suitable for pre-computation techniques and parallelization (high-performance computing–HPC). By computing the element stiffness and mass matrices from pre-computed master elements via scaling, a fully automatic HPC framework is developed. By means of six numerical examples, we demonstrate the robustness, versatility, and efficiency of the developed methodology in handling (geometrically) complex engineering problems.

Comparisons of Emotional Responses, Flow Experiences, and Operational Performances in Traditional Parametric Computer-Aided Design Modeling and Virtual-Reality Free-Form Modeling

Three-dimensional (3D) computer-aided design (CAD) is a vital tool for visualizing design ideas. While conventional parametric CAD modeling is commonly used, emerging virtual reality (VR) applications in 3D CAD modeling require further exploration. This study contrasts the emotional response, flow experience, and operational performance of design novices using VR free-form modeling (Gravity Sketch 3D) and conventional parametric CAD modeling (SolidWorks). We arranged two representative tasks for 30 participants: modeling an exact geometric shape (a cube) and a creative shape (a mug). We measured emotional response and flow experience through scales, and gathered operational performance,and further insights through semistructured interviews. The findings reveal more positive and intense emotional responses to VR free-form modeling, but its overall flow experience did not exceed expectations. No significant differences were found in concentration, time distortion sense, or control between the two techniques. Comparing modeling tasks, VR free-form modeling showed promising operational performance for early ideation, whereas conventional parametric CAD modeling proved to be more effective in 3D digitization of known shapes.

From Computer-Aided Design (CAD) Toward Human-Aided Design (HAD): An Isogeometric Topology Optimization Approach

In this paper, the novel design mode of human-aided design (HAD) is proposed to replace conventional computer-aided design (CAD). In HAD, computers can automatically complete the whole product design via a new isogeometric topology optimization (ITO), while humans just assist to slightly modify the design to meet requirements. An embedded domain ITO is presented to design complex models with irregular design domains, and editable geometric models of optimized results can be automatically generated based on layered ITO results. Three examples are tested to verify the proposed HAD mode, including a 3D cantilever beam with a regular design domain, an automotive part with an irregular design domain, and a Messerschmitt-Bölkow-Blohm (MBB) beam with a multiscale structure. The results demonstrate that the proposed HAD mode can automatically deliver high-quality optimized models; thus, it has great potential as a revolutionary technology to change the current design mode from CAD to HAD.

A coupled reinforcement learning and IDAES process modeling framework for automated conceptual design of energy and chemical systems

This study introduces an advanced automated system for designing diverse chemical or electrochemical systems, requiring minimal user expertise, and enabling designing and optimization from scratch.

Improved Compressive Properties of Lattice Structure Based on an Implicit Surface Hybrid Optimization Design Method via Selective Laser Melting

In recent years, the lattice structure produced by additive manufacturing is a type of metal foam that has been increasingly investigated for its unique mechanical properties. However, the conventional Computer-Aided Design (CAD) is inefficient, the triply periodic minimal surfaces are rarely mixed, and the smooth transitions at the boundaries are not considered. In this study, a hybrid optimization design method based on implicit surfaces is proposed, which combines multiple implicit surfaces to achieve the continuous change in the curvature at the structure junctions and reduce the stress concentration. The hybrid lattice structures designed by this method were additively manufactured using 316L alloy via a selective laser melting. The results of the finite element analysis and mechanical compression test show that the hybrid lattice structures generated by this method exhibit a higher yield strength and energy absorption. These works can be used for other implicit surfaces, improve and enrich the types of implicit surfaces, and provide more good choices for practical applications.

An in vitro comparison of the marginal and internal adaptation of ultrathin occlusal veneers made of 3D-printed zirconia, milled zirconia, and heat-pressed lithium disilicate

Statement of problemWhether additively produced zirconia could overcome problems with conventional computer-aided design and computer-aided manufacture (CAD-CAM) such as milling inaccuracies and provide accurate occlusal veneers is unclear. PurposeThe purpose of this in vitro study was to compare the marginal and internal fit of 3D-printed zirconia occlusal veneers with CAD-CAM–fabricated zirconia or heat-pressed lithium disilicate ceramic (LS2) restorations on molars. Material and methodsThe occlusal enamel in 60 extracted human molars was removed, with the preparation extending into dentin. Occlusal veneers at a thickness of 0.5 mm were designed and manufactured according to their group allocation: 3DP, 3D-printed zirconia; CAM, milled zirconia; and HPR, heat-pressed LS2. The prepared teeth and restorations were scanned and superimposed, and the marginal and internal adaptation were measured 2- and 3-dimensionally; the production accuracy (trueness) was also measured. The comparisons of the group medians were performed with nonparametric methods and a pairwise group comparison (α=.05). ResultsThree-dimensionally printed zirconia revealed median outcomes of 95 μm (margin), 252 μm (cusp), 305 μm (fossa), and 184 μm (3D internal adaptation). CAM showed median values of 65 μm (margin), 128 μm (cusp), 203 μm (fossa), and 120 μm (3D internal adaptation). The respective values for the group HPR were 118 μm (margin), 251 μm (cusp), 409 μm (fossa), and 180 μm (3D internal adaptation). Significant differences (P<.001) between CAM and 3DP (cusp, fossa, 3D internal adaptation) and between CAM and HPR (all regions) were found, with the former group showing higher accuracies. The trueness showed median discrepancies of 26 μm (3DP), 13 μm (CAM), and 29 μm (HPR) with significant differences (P<.001) for the comparisons 3DP-CAM and CAM-HPR. ConclusionsThree-dimensionally printed zirconia occlusal veneers produced by means of lithography-based ceramic manufacturing exhibit a marginal adaptation (95 μm) and a production accuracy (26 μm) similar to those of conventional methods.

Proposal of a standard for 2D representation of bio-inspired lightweight lattice structures in drawings

The interest of industrial companies for the Additive Manufacturing (AM) technology is growing year after year due to its capability of producing components with complex shapes that fit industrial engineering necessities better than traditionally manufactured parts. However, conventional Computer-Aided Design (CAD) software are often limited for the design and representation of complex geometries, especially when dealing with lattice structures: these are bio-inspired structures composed of repeated small elements, called struts, which are combined to shape a unit cell that is repeated across a domain. This design method generates a lightweight but stiff component. The scope of this work is to analyse the problem of the lattice structures representation in 2 D technical drawings and propose some contributions to support the development of Standards for their 2 D representation. This work is focused on the proposal of rules useful to represent such hierarchic structures. Python language and the open-source software FreeCad™ are used as a software platform to evaluate the suitability and usability of the proposed representation standard. This is based on simplified symbols to describe complex lattice structures instead of representing all the elements which constitute the lattice. The standard is thought to be used in technical 2 D drawings where assemblies are represented and lattice components are used (e.g. parts assembly, maintenance, parts catalogues). A case study is included to describe how the proposed standard could be integrated into a 2 D assembly drawing, following technical product documentation production typical workflow.

Dimensional accuracy and clinical adaptation of ceramic crowns fabricated with the stereolithography technique

Statement of problemThe stereolithography technique has been a promising method of fabricating fracture-resistant ceramic restorations efficiently. However, studies on the dimensional accuracy and clinical adaptation of ceramic crowns fabricated with the technique are lacking. PurposeThe purpose of this in vitro study was to evaluate the dimensional accuracy and clinical adaptation of ceramic crowns fabricated with the stereolithography technique. Material and methodsA typodont maxillary right first molar abutment tooth was scanned by using an extraoral scanner, and a crown was designed by using 3Shape Dental System CAD software. Ten ceramic crowns were fabricated with 2 different stereolithography systems, CeraFab7500 (CF) alumina and CSL150 (CL) zirconia, and a conventional computer-aided design and computer-aided manufacturing system, X-MILL500 (XM) zirconia. The crowns were scanned, and the digital casts were exported. Dimensional accuracy was measured by superimposing the digital casts with the reference model by using Geomagic Qualify software. The silicone replica method was applied to measure clinical adaptation. Results were statistically analyzed by using a 1-way analysis of variance (α=.05). ResultsCeraFab7500 reported better dimensional accuracy (41 ±11 μm) than CSL150 (65 ±6 μm) or X-MILL500 (72 ±13 μm) (P<.001). No significant difference was found between the CSL150 and X-MILL500 groups (P>.05). X-MILL500 reported significantly better adaptation in the marginal, corner, and occlusal areas but inferior adaptation in the axial area compared with CeraFab7500 and CSL150 (P<.05). Significant differences were only apparent in the axial and occlusal areas between CeraFab7500 and CSL150 (P<.05). No significant difference was found in the marginal or corner area between CeraFab7500 and CSL150 (P>.05). ConclusionsBoth CeraFab7500 and CSL150 can fabricate ceramic crowns with high dimensional accuracy and marginal adaptation within clinically acceptable limits. The results indicate that the fabrication of ceramic crowns by using the stereolithography technique seems to be promising.

Studi Literatur Tentang Penggunaan Software Autodesk Revit Studi Kasus Perencanaan Puskesmas Sukajadi Kota Prabumulih

Computer Aided Design (CAD) has long been known to document architectural design work and information, replace the manual drawing method by hand and bring significant changes in project documentation. BIM (Building Information Modeling) is a paradigm shift replacing Conventional CAD. BIM is basically a digital platform for manufacturing virtual buildings. Autodesk Revit Software is a BIM (Building Information Modeling) based software that helps document projects more realistically with three-dimensional modeling. The purpose of this research in this Final Project is to design a 2-storey building using the Autodext Revit Software for modeling and drawing. The results of the study indicate the use of BIM-based applications in designing a building can simplify the design process, improve the efficiency of time, human resources and its subsequent stages. After going through an integrated process, the final model created has all the information from the architecture, structure, and output volumes automatically.

Comparison of different cellular structures for the design of selective laser melting parts through the application of a new lightweight parametric optimisation method

Interest in lightweight geometries and cellular structures has increased due to the freeform capabilities of additive manufacturing technologies. In this paper, six different cellular structures were designed and parameterised with three design variables to carry out the lightweight optimisation of an initial solid sample. According to the limitations of conventional computer-aided design (CAD) software, a new parametric optimisation method was implemented and used to optimise these six types of structures. The best one in terms of optimisation time and stiffness was parameterised with nine design variables, changing the dimensions of the internal cellular structure and the reinforcement zones. These seven optimised geometries were manufactured in a Phenix ProX200 selective laser melting machine without using support. The samples obtained were tested under flexural load. The results show that the cubic cell structures have some advantages in terms of CAD definition, parameterisation and optimisation time because of their simpler geometry. However, from the flexural test results it can be concluded that this type of cell structure and those with horizontal bars experience a loss of stiffness compared to the estimates of the finite element analysis because of imperfections in the manufacturing process of hanging structures.

Facilitating integration of computational design processes in the design and production of prefabricated homes

ABSTRACTThis research utilizes computational design concepts to address dysfunction in the architectural, engineering and construction (AEC) sector. The goal is to identify solutions by focussing on the integration of computational design concepts into computer-aided design (CAD) processes and into compatible prefabrication strategies. Precedents are examined and project work is used to set up the modelling framework of a three-storey, prefabricated residential building, allowing reflection and speculation on solutions to the problems identified. The computational design concept of the ‘design domain’ is employed to assist with set up of the modelling framework, while computational ‘design rules’ are implemented during the developed design stage, including the ‘declarative format’ which improves accessibility using visual programming graphs, and the ‘modular format’ which reveals combined effects between programming and prefabrication strategies. The intensity of integration between these computational design, AEC CAD and prefabrication processes is assessed, allowing solutions to be developed which could improve conventional AEC CAD practice and traditional AEC prefabrication processes.

Analysis and Compact Modeling of Magnetic Tunnel Junctions Utilizing Voltage-Controlled Magnetic Anisotropy

A macrospin compact model of a perpendicularly magnetized voltage-controlled magnetic tunnel junction (MTJ) is introduced, for the evaluation of electronic and magnetic characteristics associated with its switching behavior. The voltage-driven precessional switching has been shown to outperform current-driven switching in terms of energy, speed, and bit density. However, to realize the device in embedded system memory applications, developing a compact model for simulating hybrid MTJ/CMOS circuits is necessary. This framework also needs to be compatible with conventional computer-aided circuit design tools and flows. In this paper, the voltage-controlled magnetic anisotropy effect is included as a component of the effective magnetic field in a Landau–Lifshitz–Gilbert (LLG) equation-based model. The compact model is described by Verilog-A, providing a numerical solution for a 3-D magnetization trajectory and the corresponding conductance change of the MTJ. We also include the thermal noise effect in the LLG equation to allow the evaluation of stochastic switching behavior under a wide variety of bias conditions, which can be quantified in terms of write error rate (WER). It is shown that the model allows for optimization of write pulse shape and design considerations to achieve the lowest WER for given MTJ parameters.

Retrospective future proofing of a copper mine: Quantification of errors and omissions in ‘As-built’ documentation

The electrical instrumentation control systems (EICS) ‘As-built’ documentations of a copper mine were found to possess a significant errors and omissions, which hindered the asset owner’s ability to undertake effective and efficient operations and maintenance. A Systems Information Model (SIM) was used to retrospectively create a connected system to ensure all physical equipment and the associated connections that were constructed are modelled in an object-orientated database. In creating the SIM, the existing errors and omissions in the ‘As-built’ documentation were quantified, and cost savings that could be achieved for a future planned copper mine, with a similar design, were identified. The limitations of using conventional computer-aided-design (CAD) to design and document EICS are discussed. It is recommended that retrospectively creating a SIM can provide owners and operators with significant productivity benefits as well as ensure the asset’s integrity. The case study presented provides asset owners and operators with the empirical evidence to challenge conventional thinking surrounding the design, engineering and documentation of EICS using CAD and alternatively consider the use of SIM.

3D printing of generative art using the assembly and deformation of direction-specified parts

Purpose A methodology for designing and printing three-dimensional (3D) objects with specified printing-direction using fused deposition modeling (FDM), which was proposed by a previous paper, enables the expression of natural directions, such as hair, fabric or other directed textures, in modeled objects. This paper aims to enhance this methodology for creating various shapes of generative visual objects with several specialized attributes. Design/methodology/approach The proposed enhancement consists of two new methods and a new technique. The first is a method for “deformation”. It enables deforming simple 3D models to create varieties of shapes much more easily in generative design processes. The second is the spiral/helical printing method. The print direction (filament direction) of each part of a printed object is made consistent by this method, and it also enables seamless printing results and enables low-angle overhang. The third, i.e. the light-reflection control technique, controls the properties of filament while printing with transparent polylactic acid. It enables the printed objects to reflect light brilliantly. Findings The proposed methods and technique were implemented in a Python library and evaluated by printing various shapes, and it is confirmed that they work well, and objects with attractive attributes, such as the brilliance, can be created. Research limitations/implications The methods and technique proposed in this paper are not well-suited to industrial prototyping or manufacturing that require strength or intensity. Practical implications The techniques proposed in this paper are suited for generatively producing various a small number of products with artistic or visual properties. Originality/value This paper proposes a completely different methodology for 3D printing than the conventional computer-aided design (CAD)-based methodology and enables products that cannot be created by conventional methods.

5D Building Information Modelling – A Practicability Review

Quality, time and cost are the three most important elements in any construction project. Building information that comes timely and accurately in multiple dimensions will facilitate a refined decision making process which can improve the construction quality, time and cost. 5 dimensional Building Information Modelling or 5D BIM is an emerging trend in the construction industry that integrates all the major information starting from the initial design to the final construction stage. After that, the integrated information is arranged and communicated through Virtual Design and Construction (VDC). This research is to gauge the practicability of 5D BIM with an action research type pilot study by the means of hands-on modelling of a conceptual bungalow design based on one of the most popular BIM tools. A bungalow is selected as a study subject to simulate the major stages of 5D BIM digital workflow. The whole process starts with developing drawings (2D) into digital model (3D), and is followed by the incorporation of time (4D) and cost (5D). Observations are focused on the major factors that will affect the practicability of 5D BIM, including the modelling effort, inter-operability, information output and limitations. This research concludes that 5D BIM certainly has high level practicability which further differentiates BIM from Computer Aided Design (CAD). The integration of information not only enhanced the efficiency and accuracy of process in all stages, but also enabled decision makers to have a sophisticated interpretation of information which is almost impossible with the conventional 2D CAD workflow. Although it is possible to incorporate more than 5 dimensions of information, it is foreseeable that excessive information may escalate the complexity unfavourably for BIM implementation. 5D BIM has achieved a significant level of practicability; further research should be conducted to streamline implementation. Once 5D BIM is matured and widely accepted, it is foreseeable that additional BIM dimensions of information will be incorporated into sophisticated digital building model to achieve specific project outcomes.