scholarly journals The problem of ambiguity in the task of synthesizing a wireframe model objects according to a technical drawing

2019 ◽  
Author(s):  
Валерия Тюрина ◽  
Valeriya Tyurina ◽  
Сергей Ротков ◽  
Sergey Rotkov ◽  
Татьяна Мошкова ◽  
...  
Keyword(s):  
3D Model ◽  
Complete Information ◽  
3D Models ◽  
Standard Procedures ◽  
Technical Drawing ◽  
Graphic Information ◽  
Automatic Reading ◽  
Geometric Elements ◽  
Wireframe Model

The level of quality of the wireframe model obtained in the first stage of solving the problem of restoring the image of a non-planar object depends on the completeness of using the classes of graphic information used to synthesize a 3D model according to the technical drawing. In cases where the drawing is quite simple and allows you to read complete information about the object by existing procedures of automatic "reading the drawing", it is possible to restore the frame models that are fully consistent with the synthesized object. They can be used immediately for further transformations to other types of 3D models. Such frame models are characterized by the fact that all the vertices and edges included in their structure belong to the surface of the desired object. But in most practical cases, when the simulated objects correspond to real products and their technical drawing is full of difficult to formalize information, in the structure of frame models built according to standard procedures, due to a number of objective reasons, there are false geometric elements, i.e. those that are not on the surface of the desired 3D object. This leads to the ambiguity of the restoration of a unique wireframe model corresponding to the object specified in the technical drawing, and requires the development of procedures to avoid the multiplicity of solutions.

Augmented Reality Aided 3D Modelling

2014 ◽  
Vol 1036 ◽  
pp. 1037-1040
Author(s):  
Radu Emanuil Petruse ◽  
Ioan Bondrea ◽  
Marco Sacco ◽  
Stefano Mottura
Keyword(s):  
Augmented Reality ◽  
3D Model ◽  
3D Models ◽  
Spatial Visualization ◽  
3D Modelling ◽  
Technical Drawing

The purpose of the article is to introduce possibilities of using Augmented Reality instructions in order to better understand technical drawings. The aim of these instructions based on 3D models is to create AR training applications and analyze their impact on the users. These instructions consist in a 3D model, superimposed over the technical drawing. The AR application also offers step by step instructions for 3D modelling in CAD software, which are very useful in creating the 3D model starting from a technical drawing. The AR application was tested by students from the Faculty of Engineering in Sibiu, obtaining great improvements in their 3D modelling times. The results of a survey that the students completed reveal that the AR modelling instructions also aids their spatial visualization capability.

scholarly journals Development of a method for improving the accuracy of measurement of linear measures of 3D models via scanning

2021 ◽  
Vol 6 (2(62)) ◽  
pp. 30-36
Author(s):  
Volodymyr Kvasnikov ◽  
Dmytro Ornatskyi ◽  
Valerii Dostavalov
Keyword(s):  
3D Model ◽  
3D Models ◽  
Poor Quality ◽  
Advanced Technology ◽  
Combined Method ◽  
Linear Dimensions ◽  
Photogrammetric Method ◽  
Real Size ◽  
Definition Of

The object of research is to refine the linear sizes of the obtained 3D models via scanning, and reducing the numbers of errors when obtaining the model. For now, there is no accuracy method for transferring the actual sizes of an object to a 3D model. One of the most problematic places in the existing methods of transferring sizes from the object to the model is the error in the placement of dimensional markers due to inaccuracy, or poor quality of the received surface via scanning. A model of the instrument complex is used to implement an improved method of 3D scanning, based on the photogrammetric method. The advanced technology of construction and measurement of 3D models on the basis of photos on the principle of stereo pairs in combination with image projection is based on a combination of existing scanning methods. As well as the introduction of new functionalities, such as maintaining the actual sizes of an object, its textures, color and light characteristics, as well as improving the accuracy of linear sizes. As a result of the use of a standard, reference projections, and a new method of comparing photographs to build a 3D model, a 60 % increase in the accuracy of linear dimensions was achieved. This is due to the fact that the proposed new combined method incorporates all the existing most important aspects of scanning. And also has a number of features, such as the definition of boundary surfaces, automatic sizing, detection, and processing of glass and mirror surfaces. Due to this, this method eliminates the main disadvantages of the usual photogrammetric method – inaccuracies in the surface quality of the models, and inaccuracies in the transfer of linear dimensions. It is estimated that the combined method will allow to transfer the real size of simple objects in 3D with an accuracy of 99.97 % of the actual size of the object. It will also improve the quality of complex surfaces (boundary, glass, mirror) by at least 40–60 %, compared to other existing methods.

scholarly journals Problems of Creation and Usage of 3D Model of Structures and Theirs Possible Solution

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 181 ◽  
Author(s):  
Dalibor Bartonek ◽  
Michal Buday
Keyword(s):  
Computer Aided Design ◽  
3D Model ◽  
Three Dimensional ◽  
3D Models ◽  
Cad System ◽  
Building Models ◽  
Special Cad ◽  
Aided Design ◽  
The Church

This article describes problems that occur when creating three-dimensional (3D) building models. The first problem is geometric accuracy; the next is the quality of visualization of the resulting model. The main cause of this situation is that current Computer-Aided Design (CAD) software does not have sufficient means to precision mapping the measured data of a given object in field. Therefore the process of 3D model creation is mainly a relatively high proportion of manual work when connecting individual points, approximating curves and surfaces, or laying textures on surfaces. In some cases, it is necessary to generalize the model in the CAD system, which degrades the accuracy and quality of field data. The article analyzes these problems and then recommends several variants for their solution. There are described two basic methods: using topological codes in the list of coordinates points and creating new special CAD features while using Python scripts. These problems are demonstrated on examples of 3D models in practice. These are mainly historical buildings in different locations and different designs (brick or wooden structures). These are four sacral buildings in the Czech Republic (CR): the church of saints Johns of Brno-Bystrc, the Church of St. Paraskiva in Blansko, further the Strejc’s Church in Židlochovice, and Church of St. Peter in Alcantara in Karviná city. All of the buildings were geodetically surveyed by terrestrial method while using total station. The 3D model was created in both cases in the program AUTOCAD v. 18 and MicroStation.

scholarly journals Homomorphic Encryption-Based Robust Reversible Watermarking for 3D Model

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 347 ◽  
Author(s):  
Li Li ◽  
Shengxian Wang ◽  
Shanqing Zhang ◽  
Ting Luo ◽  
Ching-Chun Chang
Keyword(s):  
3D Model ◽  
Homomorphic Encryption ◽  
Three Dimensional ◽  
3D Models ◽  
Reversible Watermarking ◽  
Histogram Shifting ◽  
Watermark Embedding ◽  
Paillier Cryptosystem ◽  
Embed Watermark

Robust reversible watermarking in an encrypted domain is a technique that preserves privacy and protects copyright for multimedia transmission in the cloud. In general, most models of buildings and medical organs are constructed by three-dimensional (3D) models. A 3D model shared through the internet can be easily modified by an unauthorized user, and in order to protect the security of 3D models, a robust reversible 3D models watermarking method based on homomorphic encryption is necessary. In the proposed method, a 3D model is divided into non-overlapping patches, and the vertex in each patch is encrypted by using the Paillier cryptosystem. On the cloud side, in order to utilize addition and multiplication homomorphism of the Paillier cryptosystem, three direction values of each patch are computed for constructing the corresponding histogram, which is shifted to embed watermark. For obtaining watermarking robustness, the robust interval is designed in the process of histogram shifting. The watermark can be extracted from the symmetrical direction histogram, and the original encrypted model can be restored by histogram shifting. Moreover, the process of watermark embedding and extraction are symmetric. Experimental results show that compared with the existing watermarking methods in encrypted 3D models, the quality of the decrypted model is improved. Moreover, the proposed method is robust to common attacks, such as translation, scaling, and Gaussian noise.

3D Rebuilding for Impeller of Centrifugal Pump Based on ICT

2011 ◽  
Vol 130-134 ◽  
pp. 1114-1118 ◽  
Author(s):  
Xiao Ping Jiang ◽  
Wei Dong Shi ◽  
Wei Li ◽  
Hou Lin Liu ◽  
Ming Gao Tan
Keyword(s):  
Centrifugal Pump ◽  
Volume Rendering ◽  
3D Model ◽  
Object Oriented ◽  
3D Models ◽  
Practical Application ◽  
Pump Impeller ◽  
Input And Output ◽  
Complex Construction

In order to rebuild 3D models for pump impeller, the total inner complex construction data must be obtained at first. With the help of ICT, 367 ICT images with high quality of two typical impellers of centrifugal Pump were collected respectively, and format conversion from RAW to BMP was fulfilled though a developed program. Volume rendering was fulfilled based on these fault images, VC++ 6.0, MFC, ADO, VTK, and a series of digital image processing. A program named ReImpeller3D was developed on reverse engineering for pump impeller. The software is object-oriented and has several input and output interfaces, and also can supply geometrical models for numerical simulation, FEM, RP, digitized production, and redesign to production either. The practical application shows that it is feasible to use volume rendering to rebuild 3D model for pump impeller.

scholarly journals The use of video camera to create metric 3D model of engineering objects

2020 ◽  
Vol 19 ◽  
pp. 59-71
Author(s):  
Nicholas Batakanwa ◽  
Tomasz Lipecki
Keyword(s):  
3D Model ◽  
Profile Analysis ◽  
Average Distance ◽  
Laser Scanner ◽  
Field Research ◽  
3D Models ◽  
Video Camera ◽  
3D Modelling ◽  
Speed Up

The article presents the possibilities of using a video camera to create a 3D metric model of engineering objects using Agisoft and CloudCompare software. Traditional photogrammetry technique does not always match up with production urgency needed by the market. Complexity is seen when used in huge objects leading to rise of cost, time and tediousness of the work. The use of Video Camera technique here termed as videogrammetry technique is comparable to taking pictures, however, it allows to speed up the process of obtaining data, which in many cases is a key element in anyb any project or research. The analysis of the quality of 3D modelling of the three filmed objects was performed, which allowed the authors to refine the procedure for acquiring images for spatial analyses. The applied technique of “videogrammetry” is comparable to taking pictures, but allows the data acquisition process to speed up, which in many cases is a key element in field research. 3D objects videos from no-metric camera were processed by Agisoft Metashape. To be able to assess the accuracy of the videogrammetry data, a well-established Laser scanner technique’s data was used for comparison. The laser scanner data were pre-processed in Autodesk Recap. Manual registration was performed utilizing 14 points from the three scans. The two 3D models were exported to CloudCompare software for comparison and further analysis. An analysis of the quality of 3D modelling of the three objects filmed was performed, which allowed refining the procedure for obtaining images for spatial analysis. The article presents the possibilities of using a non-metric mobile phone video camera “videogrammetry” to create a metric 3D model of engineering objects using Agisoft and CloudCompare software. In CloudCompare a registration, cloud to cloud (C2C) and profile to profile analysis was performed to determine the uncertainty of the 3D model produced from videogrammetry data determined as distance of separation between the two models. Results show average distance of separation between laser scanner and videogrammetry derived 3D model point cloud to be 34cm, the average profile separation was 25 cm in XY plane and 1.9 cm in Z-plane. Using Cloud to Cloud PCV the average difference of 84 cm was determined.

A Realistic Model of Human Structure from the Visible Human Data

2001 ◽  
Vol 40 (02) ◽  
pp. 83-89 ◽  
Author(s):  
B. Pflesser ◽  
A. Pommert ◽  
M. Riemer ◽  
R. Schubert ◽  
T. Schiemann ◽  
...  
Keyword(s):  
3D Model ◽  
Clinical Work ◽  
3D Models ◽  
Realistic Model ◽  
Cross Sectional ◽  
Quality Models ◽  
Inner Organs ◽  
Computer Based ◽  
Visible Human

AbstractThe computer-based 3D models of the human body reported to date suffer from poor spatial resolution. The Visible Human project has delivered high resolution cross-sectional images that are suited for generation of high-quality models. Yet none of the 3D models described to date reflect the quality of the original images. We present a method of segmentation and visualization which provides a new quality of realism and detail. Using the example of a 3D model of the inner organs, we demonstrate that such models, especially when combined with a knowledge base, open new possibilities for scientific, educational, and clinical work.

scholarly journals Impact of the method of registering Terrestrial Laser Scanning data on the quality of documenting cultural heritage structures

2015 ◽  
Vol XL-5/W7 ◽  
pp. 245-248 ◽  
Author(s):  
M. Kedzierski ◽  
A. Fryskowska ◽  
D. Wierzbicki ◽  
M. Dabrowska ◽  
A. Grochala
Keyword(s):  
Laser Scanning ◽  
3D Model ◽  
Measurement Data ◽  
Point Clouds ◽  
Complete Information ◽  
Sacred Art ◽  
Historical Structures ◽  
Essential Step ◽  
Entire Structure

When documenting historical structures and objects, especially delicate artefacts such as pieces of sacred art, only techniques that allow remote, non-contact methods that enable the most precise measurements should be used to obtain data. TLS can be considered as such a technique however in order to obtain complete information for the entire structure, there is usually a need to acquire data from more than one measuring station. In this case, the most important and essential step of processing TLS data is the registration of scans. The paper contains a description of research and analyses concerning the registration of point clouds using three methods: manual, automatic and a combination of the two. The research was carried on measurement data from a historical synagogue. The structure was divided into three parts – three scans. The accuracy with which these scans were registered was assessed and a 3D model of the interior was created.

scholarly journals Quality of 3D Models Generated by SFM Technology

2013 ◽  
Vol 21 (4) ◽  
pp. 13-24 ◽  
Author(s):  
Marián Marčiš
Keyword(s):  
Computer Vision ◽  
Camera Calibration ◽  
3D Model ◽  
Automatic Detection ◽  
3D Models ◽  
Exterior Orientation ◽  
Time Consumption ◽  
Financial Costs ◽  
Different Types

Abstract Using various types of automation in digital photogrammetry is associated with questions such as the accuracy of a 3D model generated on various types of surfaces and textures, the financial costs of the equipment needed, and also the time costs of the processing. This topic deals with the actual technology of computer vision, which allows the automated exterior orientation of images, camera calibration, and the generation of 3D models directly from images of the object itself, based on the automatic detection of significant points. Detailed testing is done using the Agisoft PhotoScan system, and the camera configuration is solved with respect to the accuracy of the 3D model generated and the time consumption of the calculations for the different types of textures and the different settings for the processing.

Criteria for evaluation of the coordinate measurements quality of parts geometric parameters at pilot-experimental production

2019 ◽  
pp. 3-8
Author(s):  
N.Yu. Bobrovskaya ◽  
M.F. Danilov
Keyword(s):  
Quality Indicators ◽  
Quality Management System ◽  
Technical Specification ◽  
Experimental Production ◽  
Technological Heredity ◽  
Coordinate Measurements ◽  
Reasonable Choice ◽  
The Stability ◽  
Geometric Elements

The criteria of the coordinate measurements quality at pilot-experimental production based on contemporary methods of quality management system and traditional methods of the measurements quality in Metrology are considered. As an additional criterion for quality of measurements, their duration is proposed. Analyzing the problem of assessing the quality of measurements, the authors pay particular attention to the role of technological heredity in the analysis of the sources of uncertainty of coordinate measurements, including not only the process of manufacturing the part, but all stages of the development of design and technological documentation. Along with such criteria as the degree of confidence in the results of measurements; the accuracy, convergence, reproducibility and speed of the results must take into account the correctness of technical specification, and such characteristics of the shape of the geometric elements to be controlled, such as flatness, roundness, cylindrical. It is noted that one of the main methods to reduce the uncertainty of coordinate measurements is to reduce the uncertainty in the initial data and measurement conditions, as well as to increase the stability of the tasks due to the reasonable choice of the basic geometric elements (measuring bases) of the part. A prerequisite for obtaining reliable quality indicators is a quantitative assessment of the conditions and organization of the measurement process. To plan and normalize the time of measurements, the authors propose to use analytical formulas, on the basis of which it is possible to perform quantitative analysis and optimization of quality indicators, including the speed of measurements.

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