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Abstract

Content

Introduction

With the development of computer technology are developing computer science. One of the most urgent in our time, the direction in computer science is to solve the problems of graphical modeling using computer technology. Our university has its own development, graphic simulation, presented in a graphical library and interactive modeling system, which provides the possibility of constructing complex drawing. These developments are aimed at improving the educational process in the disciplines that are somehow connected with a graphical modeling.

1. Relevance of the topic

The scope of our concerns is the development trend in the software as a three-dimensional modeling. There are many tools for three-dimensional modeling, each of which has its pluses and minuses. Many image editors have a huge range of possibilities, this is a plus, if necessary, most of them, but at the same time, and minus if you want a small number of possibilities. The downside is often over-inflated price of a graphical editor, this is especially noticeable when the editor is used for training purposes to show the construction of simple models or drawings. Developments in three-dimensional modeling is very relevant because of the limitations of existing software products.

2. The purpose and objectives of the study, expected results

The aim is to conduct new research and expand the range of affected areas in the field of modeling. Further development and improvement of existing development is to expand the existing library and the interactive system, so that they would provide an opportunity for creating and editing some three-dimensional geometric shapes in the graphic dialogue, as well as supporting the complex relationship between the drawing object and its three-dimensional representation. Our goal is to build a convenient and simple graphics library that allows you to create graphical editors narrow profile, ie to perform specific tasks necessary to the user.

Improvement of the library includes the following main tasks:

  1. Development of tools for building the basic three-dimensional (hereafter 3D) models of the shapes.
  2. Creation of tools supporting the possibility of manipulation of 3D shapes;
  3. Implementation of the possibility of providing the basic three-dimensional models of figures in a realistic manner;
  4. Develop a mechanism section of three-dimensional objects sites;
  5. Support for communication between the existing library, which allows you to build complex drawing, and developed an additional module, designed for modeling 3D objects.

The object of study : the relationship of complex drawing with three-dimensional objects

Subject of research : the construction of complex drawing, the generation of three-dimensional objects in a realistic form, the construction of the cross section of objects

3. Review of Research and Development

Since the geometric modeling and three-dimensional graphics were very popular in the world, the current problems in this part of the research activities have been widely studied as an American, European, Japanese scientists and national experts. Issues of geometric modeling and three-dimensional graphs a number of papers.

3.1 Overview of international sources

In the last century have been laid, the general principles of graphic design systems, standards and protocols that describe the algorithms and methods in them. These principles are well described in the book, PV Veltmandera [1]. With the increasing complexity and expansion capabilities, and improved hardware graphics systems, and the varied approaches to their design and development.

With the advent of object-oriented graphics system using the object approach in their work, they operate holistic entities possessing a set of properties and operations (methods). Due to the separation of code into components and build the class hierarchy, the design process is greatly simplified. The materials Deryabinskogo NB, Denisova EY [2] described an approach to the design of computer graphics-based object-oriented model, designed to minimize the effort required to develop.

The newest approach to designing graphics systems based on a higher level of abstraction. Component-based approach divides the target system to a set of components and services with a well defined interface. Application programmer does not need to know how the component, all that is required for its use in the system - is the knowledge of its interface, ie how to connect to the system and how to use its capabilities. Application of this approach is described in the article «Municipal GIS for Russian conditions: low-cost, scalable solutions in a standard core» of the magazine «CAD and graphics» [3]. This approach is based on the majority of the systems life cycle management of products (article of the magazine «CAD & Graphics») [4], which are integrated modules to support the visualization of models, mathematical calculations, data storage and transfer, documentation of design information, etc.

3.2 Overview of local sources

The idea of creating a system of geometric modeling that supports the correspondence between flat shapes and spatial representation, was proposed in Article V. Karabchevksogo and IV Hlepitko [5], as a learning system that allows students to carry out construction on a complex drawing, and simultaneously view the results of constructing a 3d scene. As this idea was proposed system Spin, as described in Article V. Karabchevsky [6], with a basic set of two-dimensional elements and the transformation of the projections of the segment in its three-dimensional representation. With Spin can solve such problems in descriptive geometry as a lowering of the perpendicular from a point on the plane, finding the point of intersection of the line and the plane, finding the natural size of objects, etc.

3.3 Overview of national sources

This, the system spin, Burchak IN and Velichko VL was offered a different system [7]. ProGeTeach system allows you to interactively perform the construction on the diagram Monge and on this basis to create a 3d model. In terms of primitives that are used in the construction, system capabilities are limited, there are only segments of straight lines and points.

Unlike ProGeTeah, Spin system has a wider selection of primitives that allows us to construct two-dimensional curves, such as an ellipse and a circle. Also in Spin implemented the ability to bind to the already existing constructions drawing objects, such as the intersection of lines, midpoint, end point of tench, etc. Spin is very user friendly and intuitive, even for a beginner.

4. Analysis of primary research material

The basis for the research and development was the work of our university graduates [5], this was an analysis of recent publications. In the present work was created graphics library «SPIN», but it was not until the end of realizovana.V work has the following drawbacks: a limited number of objects to build three-dimensional representation only in the form of wire, you can not view the three-dimensional objects in a realistic way.

Improvement Library SPIN is to develop the following tools:

  1. basic tools for building three-dimensional (hereafter 3D) models of figures;
  2. possible manipulation of 3D shapes;
  3. representation of the basic three-dimensional models of figures in a realistic manner;
  4. mechanism of the cross section of objects;
  5. support for the relationship between the existing library «SPIN», which allows you to build complex drawing, and developed an additional module «3DObjects», intended for modeling 3D objects.

Performing geometric transformations in space, based on the coordinates of the transition to the new coordinates of the means of general formulas [8]:

The co-ordinates of points
or its matrix representation:
Transformation matrix of coordinates of points

For the development of three-dimensional models of the manipulation of figures apply affine transformations [9]. The basis of representation of 3D objects in a realistic form is the method of constructing a BSP-tree [10]. Examples of the use of this tool, you can see in Figure 1.

Painting of three-dimensional objects

Figure 1 - Painting three-dimensional objects

Tool for cross-section of three-dimensional objects based on the following method. Initially the section plane is given, then checks the planes of the vertices of the polygonal model of three-dimensional object with respect to a plane of section [11]. The developed method section, the algorithmic side, is not effective, however, due to the simplicity and uniformity of action in this method, it is easy to apply tools and methods for parallelization, which largely compensates for the efficiency is not specified. It is also important to note that this method allows you to cross any three-dimensional models of the figures, not just the base. An example of the cross section is shown in Figure 2.

The cross section for three-dimensional objects

Figure 2 - Cross section of three-dimensional objects

The structure contains two modules:

  1. Module «SPIN», used to build complex drawings;
  2. Module «3DObjects» [12], which allows you to work with three-dimensional models of the figures;
Each module has its own workspace has its own mathematical apparatus can be operated in conjunction or independently (see Fig. 3-6).
Building a cube in 3DObjects

Figure 3 - Construction of a cube in 3DObjects

Construction of a cylinder in 3DObjects

Figure 4 - Construction of a cylinder in 3DObjects

Construction of the cone in the 3DObjects

Figure 5 - Construction of the cone in the 3DObjects

Construction of a sphere in 3DObjects

Figure 6 - Construction of a sphere in 3DObjects

Figure 7 shows the integrated use of «SPIN» and «3DObjects». This figure demonstrates the construction of complex drawing of a cone and its sections, wire and generate a realistic model for the integrated drawing.

Building a cube in 3DObjects

Figure 7 - Integrated use of «SPIN» and «3DObjects»
(animation - Resolution: 683 x 350 px; size: 116 kb; frame 7, the delay between frames: 1s, the number of iterations: 7)

Findings

As a result of the work was carried out analysis of existing publications and developments of our university, studied the existing methods for constructing complex drawing, three-dimensional objects and manipulations on them.

Surveys have achieved the following results: a graphics library which has created opportunities to build, modify, section and fill three-dimensional objects. On the basis of this library was developed an interactive modeling system that allows creation and editing of some models of geometric shapes in the graphic dialogue, as well as providing support to the complex relationship between drawing objects and three-dimensional representation.

It is planned to improve the shading algorithms, triangulation and cross-section of three-dimensional objects to create tools to perform Boolean operations, the construction of curves and surfaces with the ability to modify them, as well as refine the graphical user interface.

In writing this essay master's work is not yet complete. Final completion: December 2012. The full text of the work and materials on the topic can be obtained from the author or his head after that date.

List of sources

  1. Veltmander PV Textbook «Architectural Graphics» - (Tutorial in 3 books) Book 3 - Novosibirsk State University. - 1997. [Electronic resource]. Home Access: http://cylib.iit.nau.edu.ua/ ...
  2. Deryabin NB, Denisov, EY Object-oriented infrastructure of computer graphics. / / Proceedings of the 11th Scientific and Practical Seminar «New information technologies in automated systems» - M.: MSIEM. - 2008. - C. 10-15.
  3. Municipal GIS for Russian conditions: low-cost, scalable solutions in the standard kernel / / The magazine «CAD and graphics.» [Electronic resource]. Home Access: http://www.sapr.ru/ ...
  4. Features introduction to the facilities and methods of integration CAD/CAM/PDM/FRP/MRP/MES/PLM- and ERP-systems / / Journal «CAD and graphics.» [Electronic resource]. Home Access: http://www.sapr.ru/ ...
  5. Karabchevksy VV, IV Hlepitko Development Tools and geometric modeling systems / / Science notation. Mezhvuzovy collection (in «Engineering»). Issue 22. Part 1. «Recent developments in geometric modeling» (April 2008). - Lutsk, 2008. - P.133-137.
  6. Karabchevsky V. Computer graphics technology in teaching courses for the specialty «Software» / / Proceedings of the International scientific-practical conference «The effectiveness of engineering education in the XXI century». - Donetsk: Donetsk National Technical University. - 2001. - C. 260-267.
  7. Burchak IN, Velichko VL Program maintenance of discipline «Descriptive Geometry» for use in distance learning / / Scientific Notes. Interuniversity collection (in «Engineering»). Issue 22. Part 1. «Recent developments in geometric modeling» (April 2008). - Lutsk. - 2008. - S. 45-50.
  8. D. Rogers, «Algorithmic foundations of computer graphics»: Trans. with angl.-M., New York, 1989.-512s.
  9. D. Rogers, J. Adams, «Mathematical Foundations of Computer Graphics»: Trans. from English. - Springer-Verlag, 2001.-604s.
  10. André Lamotte. Programming three games for Windows. Tips for a professional three-dimensional graphics and rasterization.: Trans. from English. -M. Publishing House «Vilyamc» 2004.-1424s.: Ill.-Paral.tit.angl.
  11. Shikin, EV, AV Boreskov Computer Graphics. Polygonal models.: - Moscow, Dialog-MEPI, 2000.-464s.
  12. Mc-Donald. Matthew. WPF: Windows Presentation Foundation in. NET3.5 with examples in C # 2008 for professionals. 2nd Edition Hardcover. with angl.-M. LLC «ID Williams», 2008.-928s.: Ill. - A pair. tit. Engl.