scholarly journals Influence of Geometric Features Associativity of CAD Class Models on the Process of Their Updating – Comparative Analysis

2021 ◽  
Author(s):  
Grzegorz Świaczny

This article deals with the topic of one of the most important features of modern CAx class systems – associativity. The term refers to the ability to form relations (links) between two or more objects (in terms of their selected features), and with the consequence creating an associative (linked) three-dimensional model. The author pays special attention to the very process of creating relations between objects, as it has a key impact on the structural stability of CAD class models, and thus on their susceptibility to possible modifications. To show that not all associativity brings a positive effect, the author presents two examples of its implementation. In order to emphasize the influence of the method of linking individual elements, both examples are based on the same 3D model – a thin-walled part with a positioning pin. That means the geometric form of the default part is the same, whereas only relations of the individual objects of the 3D model change. In the first scenario, correctly defined relations between objects make that the positioning pin offset does not affect the initial design conditions. The second scenario shows an incorrect implementation of associativity, as a result of which the same operation of positioning pin offset gives non-compliance with the initial design conditions and with the consequence an undesirable change in its geometry. The article is an attempt to draw attention to the fact that the associative structure of 3D models is not always equal to the optimal solution. Only the well-thought-out nature of associativity allows to use all its advantages.

2019 ◽  
Vol 17 (3) ◽  
pp. 18-28
Author(s):  
E. Bykova ◽  
A. Savostyanov

Despite the large number of existing methods of the diagnosis of the brain, brain remains the least studied part of the human body. Electroencephalography (EEG) is one of the most popular methods of studying of brain activity due to its relative cheapness, harmless, and mobility of equipment. While analyzing the EEG data of the brain, the problem of solving of the inverse problem of electroencephalography, the localization of the sources of electrical activity of the brain, arises. This problem can be formulated as follows: according to the signals recorded on the surface of the head, it is necessary to determine the location of sources of these signals in the brain. The purpose of my research is to develop a software system for localization of brain activity sources based on the joint analysis of EEG and sMRI data. There are various approaches to solving of the inverse problem of EEG. To obtain the most exact results, some of them involve the use of data on the individual anatomy of the human head – structural magnetic resonance imaging (sMRI data). In this paper, one of these approaches is supposed to be used – Electromagnetic Spatiotemporal Independent Component Analysis (EMSICA) proposed by A. Tsai. The article describes the main stages of the system, such as preprocessing of the initial data; the calculation of the special matrix of the EMSICA approach, the values of which show the level of activity of a certain part of the brain; visualization of brain activity sources on its three-dimensional model.


2020 ◽  
Vol 75 ◽  
pp. 04016 ◽  
Author(s):  
Ihor Hevko ◽  
Olha Potapchuk ◽  
Iryna Lutsyk ◽  
Viktorya Yavorska ◽  
Viktoriia Tkachuk

The authors present methods building and printing three-dimensional models for graphical reconstruction of historical architectural objects. Procedure sequence of the methods is exemplified through building the model of the Parochial Cathedral of St. Mary of the Perpetual Assistance of the 1950s. After analyzing and assessing the most popular specialized software means, the 3DS Max environment is chosen to build a three-dimensional model. Suggested software tools enable increased accuracy, speed and granularity of fixation of complex systems and expanded databases, providing efficient instruments to deal with bulk data and being relevant to new IT achievements. Sequence and content of operations for analytical and modeling cycles are substantiated. The cathedral model is built on the basis of archive photographs and drafts. The authors describe methods and the algorithm of procedures, principles of architectural and spacious modeling to recreate the architectural object. The three-dimensional model is built by applying a stereogram miniature of the destroyed Cathedral. Reconstruction of spacious configuration of the objects is based on parallax assessment of images. Stages of project implementation are determined. There are described methods of implementing modeling by 3DS Max tools and preparing the model for 3D printing in Cura.


Author(s):  
Л.В. Карпюк ◽  
Н.О. Давіденко

The article discusses the methods of using the AutoCad graphic editor for creating three-dimensional objects. The possibilities of three-dimensional modeling in the AutoCad graphic editor for optimizing the educational process of bachelors of technical specialties are also considered. The article analyzes the best ways to create mechanical engineering drawings.The most developed software tool for the production of design documentation is AutoCAD - a universal graphic design system. Creating models of any complexity in space by using this graphic editor, the user will be able to see their relative position, estimate the distance between them. The model can be freely moved in space, viewing many options. The ability to control the point of view allows to conveniently select the view of the 3D model that is being developed. Zooming, panning in real time with the ability to freely rotate the camera around the model provide the ability to quickly view objects from any point of view. The article provides examples of choosing the most optimal option for creating a three-dimensional model. The traditional way to create a 3D model drawing is to make 2D views of the model. When creating a flat drawing, there is a possibility of error when making projections, since they are created independently from each other and consist of several images. It is rather difficult to represent an object in space from a flat drawing. At present, modern software graphic editors are aimed at creating three-dimensional models that allow to create realistic models and, on their basis, get two-dimensional projections. Graphic editor AutoCad allows to create three-dimensional objects based on standard commands, in the form of a cylinder, cone, box, torus, etc., when editing which you can get the desired shapes. After creating a three-dimensional model, the user can get its two-dimensional projections not only on the main planes, but also on any plane at will. The 3D modeling method allows you to create a complex drawing with any number of images based on a 3D model. There are ways to create 2D plane drawings from a 3D model and the ability to edit ready-made designs that can be inserted from model space into paper space. Editing takes place by changing the parameters of a 3D object in model space, and these changes are automatically reflected in paper space. This method allows us to use the tools to quickly create a system of 3-4 linked views for a 3D AutoCad model.


2022 ◽  
Vol 2160 (1) ◽  
pp. 012012
Author(s):  
An Qu ◽  
Tianmin Guan ◽  
Tianxiang Gan ◽  
Yuanyuan Li ◽  
Zhuang Lin ◽  
...  

Abstract In this paper, Mimics is using to reconstruct the 3D model of hemangioma from 2D cerebral angiography images. The process of 3D model reconstruction is formulated. The hemangioma model is extracted and the parameters of the hemangioma are measured, which provided a model basis for the structural design of the spring coil. The shape and structure of the coil are very important for the therapeutic effect. During the treatment, the coil is implanted into the hemangioma from outside the body through a catheter.


Author(s):  
E. Alby ◽  
P. Grussenmeyer ◽  
L. Bitard ◽  
S. Guillemin ◽  
V. Brunet-Gaston ◽  
...  

This paper is dedicated to the digitization of blocks and virtual anastylosis of an antique façade in Pont-Sainte-Maxence (France). In 2014 during the construction of a shopping center, the National Institute for Preventive Archaeological Research (INRAP) discovered a Gallo-Roman site from the 2<sup>nd</sup> century AD. The most interesting part of the site for the study is a façade of 70 meters long by nearly 10 meters high. The state of the conservation of the blocks of the façade makes them exceptional due to the question raised by the collapse. Representative and symbolic blocks of this building have been selected for a virtual anastylosis study. The blocks discovered belong to different types: decorated architectural blocks, monumental statuary elements and details of very fine decorations. The digital reproduction of the façade will facilitate the formulation of hypothesis for the collapse of the structure. The Photogrammetry and Geomatics Group from INSA Strasbourg is in charge of the digitization, the anastylosis and the development of exploratory methods for understanding the ruin of the façade. To develop the three-dimensional model of the facade, approximately 70 blocks of various dimensions were chosen by the archaeologists. The choice of the digitization technique is made according to the following pragmatic criterion: the movable objects are acquired with a scan-arm or a hand-held scanner in the laboratory and the largest blocks are recorded by photogrammetry at the repository near Paris. The expected types of deliverables are multiple: very accurate 3D models with the most faithful representation to document the objects in the best way and with optimized size model allowing easy handling during anastylosis tests. The visual aspect of the models is also a very important issue. Indeed, textures from photos are an excellent way to bring about the realism of the virtual model, but fine details of the object are sometimes blurred by the uniformity of the color of the original material. Acquisition by hand-held scanner does not provide the textures (they must be acquired according to a complementary process). The data types are therefore different depending on the acquisition. The type of rendering of the models depends therefore on precise choices to be defined optimally. After the acquisition, hypothesis for the construction of the façade must be validated and / or adapted by the anastylosis of the digitized blocks. Different cases must be taken into account. First, the reconstruction of broken blocks is done by adjusting the recovered fragments. If all the fragments discovered are close to the initial shape of the block, the process is assimilated to a puzzle of complex surfaces. If the fragments have no contact but are an integral part of the block, the proportion of hypotheses in relation to the contact pieces is changed. And finally, if the blocks are to be assembled together by superposition and thanks to a common plan, as assumed during the construction, the restitution could be based on the positions of discoveries and hypotheses based on the architectural knowledge of this period. Each of these three methods of reconstruction involves different processes. The three-dimensional model will be validated by the positioning of the blocks and extended according to the actual dimensions of the façade. Different collapse scenarios will result from this study.


2018 ◽  
Vol 63 ◽  
pp. 00010
Author(s):  
Izabela Piech ◽  
Boguslawa Kwoczynska ◽  
Artur Ciszewski

The aim of the study was to recreate, in the form of a 3D model, the Citadel fort No. 33 “Krakus” in Krakow. The data on the basis of which the three-dimensional model was made were obtained using a Leica ScanStation P40 terrestrial laser scanner, which is owned by the Faculty of Environmental Engineering and Geodesy of the University of Agriculture Hugona Kollataj in Krakow. The scope of field work included performing laser measurements, and then processing the point cloud in the Leica Cyclone 3D program and creating a full architectural model in SketchUp 2016.


2013 ◽  
Vol 475-476 ◽  
pp. 1207-1210
Author(s):  
Cheng Yu ◽  
Shi Wei Lin

Basing on the introduction in the knowledge management and E-commerce concept and main theory, this paper discusses the relationship between knowledge management and E-commerce, put forward E-commerce to build the foundation o f knowledge, information flow and organization structure for knowledge management and the thesis that knowledge management constructs the sustainable competitive advantage for E-commerce. It also compares and analyzes the knowledge management and E-commerce popular model, Proposes the individual-centered organization, knowledge and business three dimensional model and the knowledge and business system model of business process which is based on the former.


2020 ◽  
Vol 3 (2) ◽  
pp. 87-98
Author(s):  
Anastasiya A. Berdugina ◽  
Aleksandr V. Chernov

The presentation of the property in the form of a three-dimensional model has become a subject of increased interest in cadastre management over the past decades. An analysis of this area in Russia showed a virtual lack of dynamics in the development of 3D modeling. One of the reasons is the lack of structure and content of a 3D model. The article presents a formalized description of the elements of a 3D model, on the basis of which a set of criteria and their indicators was proposed and a comparative analysis of the content of 3D models of advanced foreign countries was carried out. As a result of the analysis, a formalized description of the structure and content of 3D models in accordance with the national characteristics of the countries under consideration is proposed. Based on the data obtained, the Russian model of the 3D cadastre is formalized, and ways of its modernization are proposed in accordance with the best technological solutions of the analyzed cadastral systems.


2021 ◽  
pp. 537-550
Author(s):  
А. Kovalenko

The article forms the conceptual principles of use of digital 3D model as means of cognition and display of signs of a criminal offense in criminal proceedings. A 3D model can be defined as a digital, three-dimensional image of an object, which reflects its external structure and color, accurately and proportionally reproduces the ratio of its spatial features. It can directly contain information about the shape, proportions, color and mutual placement in space of the elements of the original object. Provided the manufacturing technology is followed, the model is isomorphic to original object. Such a model serves as a means of cognition and reflection of forensically significant features of a criminal offense. The main methods for making 3D models are reconstruction (modeling) and scanning. 3D reconstruction (or 3D modeling) can be defined as the process of reproducing a 3D model of a forensic significant object based on information about it contained in the materials of criminal proceedings. The reconstructed models can be used during investigative (search) actions and for solving organizational problems. 3D scanning consists in the direct fixation of the external spatial features of the object using a special software and hardware complex, followed by the formation of a digital three-dimensional model of the object. Subject to compliance with the procedural requirements for the use of technical means of fixing forensically significant information, scanned 3D models will be sources of evidentiary information in criminal proceedings. 3D scanning is a promising method for recording the course and results of an inspection of the scene of an incident, inspection of a corpse or things; it can be used for fixing signs of a person's appearance, as well as for solving identification and diagnostics tasks in forensic activities. The invariability of the 3D model can be ensured by calculating the hash of the file that contains it.


2018 ◽  
Vol 224 ◽  
pp. 04027 ◽  
Author(s):  
Rimma Tukaeva ◽  
Vitalliy Afanasenko ◽  
Petr Kulakov

The main elements of most mass-transfer columns of industrial enterprises are contact trays which are formed by various details inside the apparatus. The dimensions of the details are standardized and regulated by regulatory documents. under modern conditions of equipment designing it is necessary to develop three-dimensional model of typical assembly units, that is a very time-consuming task. The article considers the way to improve the design efficiency by automation of the process of standard mass-transfer valve tray model development in Kompas 3D system with MySQL application.


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