3D Parametric Model Research Articles

HBIM to recovery the trulli in Apulia (Southern Italy)

Abstract This contribution describes an ongoing research conducted by the ISPC - CNR of Lecce, relating to the implementation of a project with BIM software and related to the recovery of n. 3 trulli located in Apulia in the countryside of Martina Franca (Taranto - Southern Italy). Research aimed at the restoration and related scheduled maintenance of the same. HBIM (Historical or Heritage Building Information Modeling) is a process applied to existing buildings that increases the potential of the BIM method, extending its use to the creation of models of existing buildings. The technologies of digital photogrammetry and laser scanner detection are used to collect information in the HBIM, which also thanks to the possibility of associating geometric information with images, make it possible to obtain a virtual model faithful to reality. From the processing based on the survey data, we then move on to the creation of libraries with parametric objects that represent all the components of the artifact. The step to get to the true digitization of the model consists in the reconstruction of the BIM model of what was detected. In fact, from a three-dimensional surface that depicts the surveyed work it is necessary to create a parametric 3D model. Through the merger of the data, an HBIM model is thus constructed that contains all the information relating to the history of the building, from which the production of technical drawings, 3D documentation, sections, details and schedules will derive. In conclusion, the geometric models thus obtained, through the surveys, must constitute indexes of contents, with data that can be consulted regarding the history, technical characteristics of the individual components, the state of deterioration of the work, in short, a range of information, all included in the associated database, and therefore usable at multiple levels of interest.

Внедрение методов суперкомпьютерной оптимизации в процесс проектирования водометных движителей

Object and purpose of research. This study discusses fast boats and waterjet propulsors. The purpose is to design a waterjet impeller shape to required conditions by means of supercomputer-based optimization with further validation of results at sea trials. Materials and methods. The optimization process is governed by a Russian software package pSeven. The computation core is Star CCM+ (Siemens). Parametric 3D model of the impeller is generated in BladePlus software (in-house KSRC development). Hydrodynamic parameters of waterjet are calculated as per CFD methods. Viscous flow parameters are found through the control-volume solution of unsteady Reynolds equations (URANS) closed by the bi-parametric semi-empirical turbulence model. Main results. The optimization studies yielded new shapes for impellers, stators and flow parts of waterjets. These solu-tions are more efficient than the prototype thanks to greater thrust of the propulsion system and lower resistance of the flow part without prejudice to good cavitation performance. Calculated hydrodynamic parameters of waterjets and the estimates for achievable speed of fast boats have been confirmed by the sea trials. Conclusion. Supercomputer optimization ensured successful beginning of the development of Russian waterjet family for fast boats not inferior to universally recognized market leaders in terms of performance parameters.

Historic Timber Roof Structure Reconstruction through Automated Analysis of Point Clouds.

We present a set of methods to improve the automation of the parametric 3D modeling of historic roof structures using terrestrial laser scanning (TLS) point clouds. The final product of the TLS point clouds consist of 3D representation of all objects, which were visible during the scanning, including structural elements, wooden walking ways and rails, roof cover and the ground; thus, a new method was applied to detect and exclude the roof cover points. On the interior roof points, a region-growing segmentation-based beam side face searching approach was extended with an additional method that splits complex segments into linear sub-segments. The presented workflow was conducted on an entire historic roof structure. The main target is to increase the automation of the modeling in the context of completeness. The number of manually counted beams served as reference to define a completeness ratio for results of automatically modeling beams. The analysis shows that this approach could increase the quantitative completeness of the full automatically generated 3D model of the roof structure from 29% to 63%.

Geometric Variability in Parametric 3D Models: Implications for Engineering Design

Modern manufacturing companies operate in environments characterized by increasingly shorter development cycles and the need to develop highly customizable products at competitive prices. In this paper, we examine the role of parametric 3D modeling in the product development process, and highlight the importance of robustness, flexibility, and responsiveness to geometric variations, which are particularly relevant in the context of the Model-Based Enterprise (MBE). We discuss the often-inefficient parametric 3D modeling practices used in industry, their root causes and implications, and identify the detrimental effects of low-quality models on engineering design activities, specifically design changes during development, generative design algorithms, design optimization, simulation, product/part family configuration, AI-based parametric modeling, Model-Based System Engineering (MBSE), and parametric and adaptive encryption. Finally, we present future lines of research aimed at increasing the quality of parametric models.

Patient-specific palatal obturator prosthesis from DICOM files through low-cost 3D printing: A case study

This work aims to define an accessible workflow for the design and manufacturing of maxillofacial obturator prostheses from DICOM files for patients with reduced mobility of the oral cavity. Starting from a case study, the STL file of the injured area was generated to develop the parametric 3D model of the mold. The mold was then manufactured with a low-cost 3D printer, and the palatal obturator was obtained by silicone casting. The patient has improved his quality of life by recovering some vital functions. This workflow may overcome conventional processes, leading to develop new patient-specific prostheses in critical situations.

Integrated Intelligent CAD System for Interactive Design, Analysis and Prototyping of Compression and Torsion Springs

This paper presents the development and implementation of integrated intelligent CAD (computer aided design) system for design, analysis and prototyping of the compression and torsion springs. The article shows a structure of the developed system named Springs IICAD (integrated intelligent computer aided design). The system bounds synthesis and analysis design phases by means of the utilization of parametric 3D (three-dimensional) modeling, FEM (finite element method) analysis and prototyping. The development of the module for spring calculation and system integration was performed in the C# (C Sharp) programming language. Three-dimensional geometric modeling and structural analysis were performed in the CATIA (computer aided three-dimensional interactive application) software, while prototyping is performed with the Ultimaker 3.0 3D printer with support of Cura software. The developed Springs IICAD system interlinks computation module with the basic parametric models in such a way that spring calculation, shaping, FEM analysis and prototype preparation are performed instantly.

Finite element analysis in the modeling of the heart and aorta structures

Rationale: 3D modeling of various anatomical structures has recently become a separate area of topographical, anatomical, and biomechanical studies. Current in vivo visualization methods and quantitative analysis in silico allow to perform the precise modeling of these processes aimed at investigation into the pathophysiology of cardiovascular disorders, risk prediction, planning of surgical interventions and virtual refinement of their separate stages.Aim: To develop tools for elaboration, analysis and validation of personalized models of various structures of the heart and aortal arch taking into account their morphological characteristics.Materials and methods: We used the results of 14 computed tomography studies from randomized patients without any disease or anomaly of the heart, aortic valve and aortal bulb. The analysis and subsequent transformation of the images were done with Vidar DICOM Viewer, SolidWorks 2016, VMTKLab software. For the FSI modeling of the aortic arch based on the results of functional multiaxial computed (MAC) coronarography (a female patient of 55 years) we developed a personalized model of the ascending aorta and aortic arch at the beginning of the systole. Using HyperMesh software (Altair Engineering Inc., USA) we have built a network of finite element of the luminal area, adventitia, and aortic media. To model mechanical properties of the aortic structures we used an anisotropic hyperelastic material model by Holzapfel – Gasser – Ogden. Material modeling, choice of the limiting antecedents, and analysis of fluid-structure interaction were performed with Abaqus CAE 6.14 software (Simulia, Johnston, USA). Adaptive image meshing by Young was used to elaborate the finite element template of the left ventricle. The algorithm was realized within the IDE PyCharm software media in Python 3.7. The algorithm was realized based on the open-source libraries OpenCV, NumPy, Matplotlib, and SciPy.Results: The first stage of the development of the aortic valve model included the design of its virtual 3D template. Thereafter, a cohesive geometric model was elaborated. Subsequent stage of the work included the transformation of the aortic valve geometric model into the parametric one. This was done through the use of the “Equations” tool within the SolidWorks. No problems with geometry of the model during its deformation were identified. Aortic segment modeling was based on the data obtained by functional MAC coronarography. Based on this and on Inobitec Dicom Viewer software, we generated a multiplane reconstruction of the zone of interest including anatomical structure of the heart and aortic valve. With the resulting set of contours, we created a 3D model, which then was converted into a polygonal stereolithographic model. We developed an algorithm for adaptive meshing to elaborate a polygonal template capable of deformation that can be used for registration both with the net methods (B-Spline) and based on the image characteristics (homologous pixels). Conclusion: The resulting parametric 3D model of the aortic valve anatomical structures is capable of adequate transformation of its geometry under external factors. It can be used in simulators of endovascular cardiosurgical procedures.

Geo-environmental parametric 3D models of SARS-CoV-2 virus circulation in hospital ventilation systems

The novel coronavirus, SARS-CoV-2, has the potential to cause natural ventilation systems in hospital environments to be rendered inadequate, not only for workers but also for people who transit through these environments even for a limited duration. Studies in of the fields of geosciences and engineering, when combined with appropriate technologies, allow for the possibility of reducing the impacts of the SARS-CoV-2 virus in the environment, including those of hospitals which are critical centers for healthcare. In this work, we build parametric 3D models to assess the possible circulation of the SARS-CoV-2 virus in the natural ventilation system of a hospital built to care infected patients during the COVID-19 pandemic. Building Information Modeling (BIM) was performed, generating 3D models of hospital environments utilizing Revit software for Autodesk CFD 2021. The evaluation considered dimensional analyses of 0°, 45°, 90° and 180°. The analysis of natural ventilation patterns on both internal and external surfaces and the distribution of windows in relation to the displacement dynamics of the SARS-CoV-2 virus through the air were considered. The results showed that in the external area of the hospital, the wind speed reached velocities up to 2.1 m/s when entering the building through open windows. In contact with the furniture, this value decreased to 0.78 m/s. In some internal isolation wards that house patients with COVID-19, areas that should be equipped with negative room pressure, air velocity was null. Our study provides insights into the possibility of SARS-CoV-2 contamination in internal hospital environments as well as external areas surrounding hospitals, both of which encounter high pedestrian traffic in cities worldwide.

APPLICATION OF PARAMETRIZATION OF CHARACTERISTIC CROSS SECTIONS OF OBJECTS FOR INDIRECT PARAMETRIZATION OF THEIR 3D MODELS IN AUTOCAD CAD

The developed algorithm of indirect parametrization of 3d model of a typical part by means of parametrization of its longitudinal section is presented in the work. Controlling the shape of 3d objects by parameterizing their 2d cross-sections allows, using AutoCAD CAD, to create variants of electronic models of parts, the same type in geometry and different in size characteristics. This saves resources that are spent on design work. The proposed algorithm for creating parameterized 3d models in the CAD environment AutoCAD can be used in engineering practice. Currently, methodological developments have been introduced into the educational process at the Kyiv Polytechnic Institute named after Igor Sikorsky when teaching the course "Engineering and Computer Graphics".

Parametric 3D modeling of young women's lower bodies based on shape classification

Three-dimensional (3D) human body modeling is an important research direction in the field of clothing virtual design. On the basis of 3D human body scanning, this paper studied a method to build a 3D parametric lower body model according to body classification. The research includes three main parts. (1) Anthropometry and body shape classification. We randomly selected 333 young women ages 18–25 years old in Northeast China as the experimental sample. Then we divided the lower body shape into three categories using principal component analysis and K-means clustering. (2) Determination of feature cross sections and points, and reconstruction of feature curves. According to the average values of each body type, we obtained the mean reference body by Euclidean distance method. We determined feature cross sections and points, and extracted the 3D coordinates of the feature points of the mean reference body to reconstruct the feature curves. (3) The surface lofting and establishment of parametric 3D lower body model. According to the shape characteristics of the lower body, we constructed the guiding lines for the crotch and lower limbs, and established parametric lower body models for three body types. Relevance to industry3D human modeling is an important part of garment industry digitization. This research provides an effective way to construct a parametric 3D lower body model. The method offers a reference for the parametric virtual human modeling and virtual fitting of trousers.

Using computer modelling when creating a heat exchanger for a complex cycle small-size gas turbine plant

Using the complex methodology of computer-aided design, calculation, and production, an experimental plate heat exchanger for a small-size gas turbine plant of complex cycle was created. Using a computer parametric 3D model of the base heat exchangers element (plate) allows for the design, calculation, optimization, and technological preparation of production automatically.. Experimental studies of the heat exchanger for the complex cycle small-size gas turbine plant created according to the proposed methodology confirm its reliability and accuracy.

Parametric FEM modeling of multilayer castellated canted cosine theta (CCT) magnets

Canted cosine theta (CCT) magnets have received increased attention in the recent years due to their inherent characteristics of high field quality and low conductor stresses, as each turn is supported by the metallic former. CCT geometry is suitable for complex magnets—such as nested dipoles, which allow full 360° control of the magnetic field direction. Modeling and design of such magnets is the subject of this work. A parametric 3D modeling framework for multilayer CCT magnets has been developed and optimized allowing efficient model generation without a need for both: CAD software and time consuming meshing. The model has been created using the APDL scripting language and solved using the Ansys software. By direct generation of nodes and elements the time to generate a model with one million elements was of the order of 10 min. A framework for script generation was developed, as well as the relations between the mesh parameters and the total number of nodes and elements. Detailed mesh dependence study was carried-out with in-depth analysis of solver performance (solution time, amount of written data, RAM requirements). Global and local convergence criteria were introduced to find the optimal mesh size. The case of a four layer 2.5 Tm nested dipole was analyzed in details including the worst-case scenario with full debonding between the CCT layers. Thanks to the castellations the nested-dipole is safe to support 144 000 Nm of torque due to Lorentz forces even with full de-bonding between the layers.

Data-Driven Deformable 3D-2D Registration for Guiding Neuroelectrode Placement in Deep Brain Stimulation.

Deep brain stimulation is a neurosurgical procedure used in treatment of a growing spectrum of movement disorders. Inaccuracies in electrode placement, however, can result in poor symptom control or adverse effects and confound variability in clinical outcomes. A deformable 3D-2D registration method is presented for high-precision 3D guidance of neuroelectrodes. The approach employs a model-based, deformable algorithm for 3D-2D image registration. Variations in lead design are captured in a parametric 3D model based on a B-spline curve. The registration is solved through iterative optimization of 16 degrees-of-freedom that maximize image similarity between the 2 acquired radiographs and simulated forward projections of the neuroelectrode model. The approach was evaluated in phantom models with respect to pertinent imaging parameters, including view selection and imaging dose. The results demonstrate an accuracy of (0.2 ± 0.2) mm in 3D localization of individual electrodes. The solution was observed to be robust to changes in pertinent imaging parameters, which demonstrate accurate localization with ≥20° view separation and at 1/10th the dose of a standard fluoroscopy frame. The presented approach provides the means for guiding neuroelectrode placement from 2 low-dose radiographic images in a manner that accommodates potential deformations at the target anatomical site. Future work will focus on improving runtime though learning-based initialization, application in reducing reconstruction metal artifacts for 3D verification of placement, and extensive evaluation in clinical data from an IRB study underway.

РАЗРАБОТКА ЭЛЕМЕНТОВ АВТОМАТИЗИРОВАННОЙ СИСТЕМЫ ПРОЕКТИРОВАНИЯ ПРИВОДОВ ГЛАВНОГО ДВИЖЕНИЯ МЕТАЛЛОРЕЖУЩИХ СТАНКОВ С ФОРМИРОВАНИЕМ ТЕХНИЧЕСКОЙ ДОКУМЕНТАЦИИ В КОМПАС–3D

The aim of the work was to develop elements of an automated design system for the main movement drives of metal–cutting machines. As automated subsystems, design modules for belt drives, couplings, gearboxes, spindle assemblies and a module for selecting an electric motor to drive the main movement of metal–cutting machines have been developed. Also, for all the developed modules, automated generation of design documentation in the Compass–3D system is provided, namely, parameterized 3D models and associative drawings of the elements of the main movement drives of metal–cutting machines. The developed automated design system will allow you to quickly calculate the elements of the main movement drives and will allow you to visualize the work by building 3D models of the elements that make up the drives, as well as quickly recalculate their parameters when the source data changes. Also, the elements of the developed automated design system can be used both in specialized educational institutions for the purpose of working out and visualizing the knowledge and skills acquired by students, and in machine–building enterprises for the purpose of approximate evaluation of design options at the stage of preliminary design of equipment. Users of the program can be students or employees of enterprises with a basic level of training in the technical direction.

Synthesis and Visualization of Image Datasets of Parametric 3D Model for Neural Network Training and Testing in Data-Poor Conditions

Synthesis and Visualization of Image Datasets of Parametric 3D Model for Neural Network Training and Testing in Data-Poor Conditions

Propeller optimization for underwater propulsion

Annotation. This article is devoted to the optimization of an underwater propulsion propeller and the identification of the main dependencies in the first stages of optimization. A mathematical model and a parameterized 3d model with indication of variable parameters, as well as optimization criteria, are presented. The used method of numerical hydrodynamic modeling is described. The obtained characteristic dependencies are presented in the form of graphs.

Prediction of cutting forces and soil behavior with discrete element simulation

A Discrete Element Method (DEM), a computerized testing rig and a soil bin were used to explain soil profile deformation caused by mouldboard plough. By using DEM, the motion of particles is given by collisions between particles. Soil-tillage tool interaction simulation was established by a 3D geometry of a mouldboard plough created using PTC Creo Parametric 3D Modelling software and soil bed modeled by discrete element particles using EDEM software. A bond element was introduced between particles and cohesion of soil was formed to create a simulation of the actual cohesive soil. The horizontal and vertical forces and soil disturbance in terms of bulk density at different speeds and depths were investigated. However, the simulation experiments followed the field experiments which were conducted using a computerized testing rig. Further, reaction forces on the plough and the resulting bulk densities were estimated from the simulated results and compared with the actual results from the field. Also, the accuracy of the developed model to predict soil displacement was measured and compared with the soil bin data with the average relative error of 1.317%. The simulated results of horizontal, vertical forces and bulk density matched well with the results obtained in the field experiment with the relative error of 4.435, 3.029 and 3.119% respectively. The vertical force provided the best regression results of 0.9948 R2 with RMSE of 0.5964, followed by 0.9884 R2 with RMSE of 0.4089 and 0.8391 R2 with RMSE of 0.5441 for horizontal force and bulk density respectively. All regression results were obtained at p<0.05. The ANOVA test showed that the p-values for the horizontal force, vertical force and bulk density were 0.753, 0.695 and 0.025 respectively. There was no significant difference between the simulation and experiment results for cutting forces while there was a significant difference for the bulk density at p<0.05. This model can be applied as an accurate, consistent and fast method of effective prediction of the final soil condition and forces needed for tillage operation.

СТВОРЕННЯ ПАРАМЕТРИЧНОЇ МОДЕЛІ ПОВЕРХНІ ТРИКОТАЖУ ПЕРЕПЛЕТЕННЯ ЛАСТИК 2x2

This study aims to develop an algorithm for constructing surface models (macro-models) of rib knitted structures, for three-dimensional modeling of tensile deformations in coursewise direction and predicting the physical and mechanical characteristics of knitted fabrics and products. During the research, methods of theoretical analysis, spline theory, computer graphics, programming tools have been used. As a result of the research, it was found that for modeling of some physical and mechanical characteristics of knitted rib structures in a deformed state, it is advisable to use geometric models that reproduce the geometry of the knitted fabric surface with high accuracy, but do not have detailed structure at the level of fibers and threads. If necessary, the values of air permeability, thermal conductivity and others porosity for such models can be taken into account under the form of appropriate indexes. At the same time, to calculate the coefficients of porosity and air permeability, one can use both experimental data and 3D models with a higher detailed structure of the textile material (meso-model). In the course of research a set of geometrical characteristics of samples of rib knits patterns is formed. Samples of 2x2 rib knits of PAN yarn of 31х2 tex have been made with a flat bed knitting machine of 10th gauge. The samples were suspended in the clamps of the relaxometer type "rack" and loaded with weights weighing from 20 to 120 g with an interval of 20 g. By means of the camera, the geometrical characteristics of the knitted surface in dry-relaxed state and in 6 discrete tensile states were recorded and determined. According to the obtained data, parametric 3D models of the knitted surface were built. An algorithm for constructing a macromodel of knitted rib 2x2 structure in the process of stretching in the coursewise direction, taking into account the peculiarities of the situational change in the geometry of the thread within the report has been developed. Three-dimensional parametric models of knitted surface (macro-models) of knitted 2x2 rib structures in the Autodesk Inventor environment have been created.

OTSun, a python package for the optical analysis of solar-thermal collectors and photovoltaic cells with arbitrary geometry.

Ray tracing software systems are commonly used to analyze the optics of solar energy devices, since they allow to predict the energy gains of devices in real conditions, and also to compare them with other systems constantly emerging in the market. However, the available open-source packages apply excessive simplifications to the model of light-matter interaction, making that the optical behaviour of the systems can not be properly characterized, which in turn implies disagreements between physical experiments and computer simulations. We present here the open source python package OTSun, which applies the Fresnel equations in their most general form, without further simplifications, and is suitable for the simulation of both solar-thermal and photovoltaic systems. The geometrical objects used in this package are created using the parametric 3D modeler FreeCAD, which is also a free and open source program and allows for the construction of arbitrary geometries that can be analyzed with OTSun. These, and other software capabilities, make OTSun extremely flexible and accurate for the optical analysis of solar devices with arbitrary geometry. Additionally, OTSun has a companion webtool, OTSunWebApp, that allows for the usage of certain features of the package without the need to install anything locally. We also show here two numerical experiments that we performed in order to validate the model and implementation: The analysis of the optical efficiency of a Linear Fresnel Reflector (with moving objects), and of a second surface mirror (with variable wavelengths). In each case, the numerical computations had deviations of less than 0.25% from reference models (either computed with another program or with exact formulas).

Design and Fabrication of Complex-Shaped Ceramic Bone Implants via 3D Printing Based on Laser Stereolithography

3D printing allows the fabrication of ceramic implants, making a personalized approach to patients’ treatment a reality. In this work, we have tested the applicability of the Function Representation (FRep) method for geometric simulation of implants with complex cellular microstructure. For this study, we have built several parametric 3D models of 4 mm diameter cylindrical bone implant specimens of four different types of cellular structure. The 9.5 mm long implants are designed to fill hole defects in the trabecular bone. Specimens of designed ceramic implants were fabricated at a Ceramaker 900 stereolithographic 3D printer, using a commercial 3D Mix alumina (Al2O3) ceramic paste. Then, a single-axis compression test was performed on fabricated specimens. According to the test results, the maximum load for tested specimens constituted from 93.0 to 817.5 N, depending on the size of the unit cell and the thickness of the ribs. This demonstrates the possibility of fabricating implants for a wide range of loads, making the choice of the right structure for each patient much easier.