Multilevel Functional-logic Models in 3D-simulators of Electrical
Equipment
A.L. Safonov1, D.I. Kopeliovich1
safonoval@yandex.ru | dkopeliovich@rambler.ru
1
Bryansk State Technical University, Bryansk, Russian Federation
At present, much attention is paid to the training of specialists who operate at responsible and hazardous industries, using various
types of benches and simulators. A special place among them is occupied by three-dimensional computer simulators, which are
characterized by low cost and sufficient quality of training. The paper presents an approach to developing an integrated control system
for computer simulators; its functional chart is proposed. In this work, the problem of modeling complex technical systems taking into
account the criteria of complete and realistic modeling and performance is specially noted. There is also an approach to constructing
simulators with variable technical object models depending on the target and with a given level of detail. The results of the work were
tested in the development of simulators of electrical equipment.
Keywords: computer simulators, computer graphics, specialist training, complex technical systems.
the speed and lack of delays in the operation of the computer
1. Introduction application largely depends on the properties of 3D models of
technical systems.
Gaining practical experience in dealing with complex
Objects in 3D application development systems can be
technical systems is an integral part of training. This is primarily
created in different ways: within the environment, by importing
connected with hazardous industries, as well as with those where
a model, they can have different shapes and complexity, but all
errors and accidents can lead to significant economic losses.
of them are represented as polygon meshes which is a set of
Such activities are characterized by the use of expensive
vertices, edges and faces that define the shape of a polyhedral
equipment, maintenance and repair of which are also not cheap,
object in 3D computer graphics and solid modeling. Objects are
for example, the control of oil and gas equipment units, electric
colored in certain colors or specially prepared raster objects
power facilities, special types of vehicles.
(textures) are placed on them with the help of specially written
Modern technologies allow to replace the use of full-scale
shaders (programs designed to provide vital information about
training in testing grounds by training methods in specialized
your video card and graphics processor (GPU)). To display a
computer systems. The most interesting application for such
polygon mesh, it must pass through a video processor for
tasks is three-dimensional computer simulators (3D simulators),
processing and rendering.
which realistically simulate technical systems, form highly
Models of complex technical systems consist of a large
qualified specialists [1].
number of bodies with different geometries. Often, most of them
In open sources, including the market of information contain curved features that require thousands or even more
systems, a significant number of computer simulators are
elements to be represented by polygon meshes in order to render
presented, although the problem of developing realistic
the model correctly.
simulators has not been fully solved yet. First of all, this is
Several approaches can be used to reduce the computational
connected with the modeling of complex technical systems, complexity of models [1]:
which should be characterized by sufficient detail of objects and
1. Using simple shaders.
at the same time have high performance. The paper deals with
2. Visualization technique with different levels of detail
the methods of modeling such systems.
(levels of detail, LOD).
3. Using MIP (a texturing method that uses multiple copies
2. Simulators of the same texture with different details. The name comes from
Early graphic applications were made practically from the latin "mutuum in parvo" which means "much in small").
scratch, now they are developed by means of ready-made tools Professional 3D simulators are widely represented at the
(game engine). This allows developers to reduce project time and market. For example, KIT 3D system of Dipol company (Fig.1
improve its quality. shows a simulator operating with power lines), simulators of
Along with the availability of a wide range of tools for United 3D Labs company and other solutions [5].
developing 3D-simulators, there are several tasks of their
implementation for complex technical systems (for example,
electricity generation facilities), which require the development
of a methodological approach that takes into account the
peculiarities of the subject area, limitations on hardware and
software, the possibility of combining with other components in
integrated software solutions [4].
The most important issue in developing simulators is the
balance of performance/details of the model (price/quality).
The main aspects affecting the performance of the model
concerning simulators are:
1. Perfection of 3D-engines.
2. Detail level of objects.
3. The quality of developing application logic (algorithm
optimality).
No matter how advanced is the logic of operating with
models meaning its performance in the framework of developing Fig. 1. KIT 3D power line model of Dipol company
simulators and how "fast" is the engine on the selected platform,
Copyright © 2019 for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
They are made in the form of separate applications, which
allows to use all the resources of the computer station, in contrast
to the system on the web-platform considered in this paper. For
complex models and simulators these systems are demanding of
hardware. At the same time, some of the objects of the
environment related to the subject matter of the simulator are not
presented accurately and fully enough. For example, as Fig. 1
shows, wire fastening to the power line insulators does not match
the correct solution with the help of helical ties.
3. Selection of 3D-simulator System Architecture
To define the rational architecture of the system, which
determines the main ways of interacting its elements, the key
point is selecting the target platform of 3D applications (scenes).
This will largely affect the properties (capabilities) of both the
visual part of 3D simulator and the choice of technologies and
methods of interaction with other parts of the system.
Evaluation criteria of the target platform are the following: Fig. 2. General system architecture.
1. Ease of control.
2. Restrictions on computing resources (object granularity, At present, there are a huge number of game engines, from
number of polygons). GameMaker, Cocos2D, Marmalade to Unity3D and Unreal
3. Memory size limits. Engine [3]. Many issues are not disclosed in official sources, you
4. Graphics restrictions (quantity and quality of textures, need to seek help in the Internet resources.
using shaders). Game Maker is more focused on beginners just starting to
5. Networking with the server (possible architecture, develop games. It is rather easy to learn it, but the possibilities of
messaging frequency, message size, etc.). Game Maker are limited.
6. Methods of distribution (sales): SaaS-platform, full Cocos2D is optimized for the development of two-
packaged type, distribution through app stores (App Store, dimensional games. The engine is not suitable for modeling data
Google Play, Amazon). simulators.
There is a variant of implementing 3D applications by means With the help of Marmalade such well-known games as
of cross-platform supporting, i.e. the possibility to implement "Plants vs. Zombies" and "Godus" were created. One of its most
one developed project through several system types. In most significant drawbacks was that the community of Marmalade
cases, this is problematic due to the different requirements for specialists is not big.
different technologies (specifications, file structure, I/O devices So, among the major alternatives only Unreal and Unity are
and product distribution methods). Therefore, in 3-D simulators the most common options for developing 3D applications.
project it was decided to focus on one specific option, and in the Unity3D engine was selected for 3D simulators project.
future to develop an alternative option involving own free labour The key findings of comparison:
force(for example, an option with large highly detailed models, Unity is much easier to learn and understand. C# language is
or, on the contrary, one that is easy to use in mobile devices). used for Unity scripting.
Below are the options for implementing 3-D simulators Unity is cross-platform, i.e. the same code written in Unity
project, which are more or less suitable for it. engine with minimal changes can be transferred to different
1. Mobile devices. platforms (PC, Mac, Android, iOS, Web, game consoles)
2. Personal computer (Windows, Mac, Linux). Unity is widely used by other developers, so there is an
3. Consoles opportunity to get high-quality and fast support and take
4. Web application in web browsers. advantage of a large number of already developed resources.
5. VR (virtual reality environment)
Analyzing the features of these platforms and the need to link 4. Development of 3D simulators
3-D simulators project in a single system with other modules In the system of 3D simulators Unity-application is an
(training, statistics, administration) we determine to use Web- interactive part of the system, where the user interacts directly
platform (players, WebGL) as the main implementation option with the models of technical objects (he trains or performs tasks).
with the ability to switch to another platform quickly. The application itself is cross-platform, and in the developed
Fig. 2 shows the architecture of the software system, which system this application is a WebGl-package, executed in the
is a classic version of 3-level web-system: client-server-data browser environment. The tools of Unity 3D allows to develop a
stores. virtual environment, including that one operating within the
Game engine is the central software component of computer framework of certain physical laws, and then put into this
video games and other interactive applications with graphics environment a user-controlled object giving it the functions of
processed in real time. It provides core technologies, simplifies interaction with the surrounding space and objects.
development, and often gives the game an ability to run on For example, Fig. 3 presents the model of 110/10 kV
several platforms. The game engine includes a whole range of distribution station (Unity-application).
applications, including rendering engine (visualizer) for 2D or Here are the principal units of the system: steel structures,
3D graphics, physics engine, sound, animation, artificial elements of operational control (cabinets, control panel), the
intelligence, network code, memory control, graphics scenes. building with the equipment. The controls are interactive: there
That is, all parts of the code written by programmers for the is a possibility to change the state of objects (turn on/off switches,
development of the game are components of the engine [2]. open doors, etc.).
5. Ensuring the Performance of Simulators Using
Models of Complex Technical Systems
The information model and using the tools of the proposed
approach allowed to develop three-dimensional simulators of
technical objects: station areas, power lines, etc.
However, often training how to work with complex systems
requires simulation models, which should ensure maximum
compliance with the original objects. For example, power
distribution units of electrical stations, control panels, etc. These
systems have a large number of relatively small objects, which
cannot be ignored or greatly simplified in models for simulators-
this will lead to a mismatch with the original and disrupt the
Fig. 3. Unity-application with the model of 110/10 kV training process. In such models, with a "direct approach" to
modeling, the number of polygons can reach tens of millions,
distribution station.
which significantly affects the performance of the system,
Software development allows to provide for the interaction influencing the time of rendering (frame rendering) and RAM
of application objects, including the process logic of simulator used.
A slight improvement is achieved by using LOD technology
tasks.
– a technique in three-dimensional graphics programming, which
3D simulators should provide the formation of competencies,
the main of which are: consists in the creation of several hierarchically nested levels of
1. Knowledge of the design of technical systems in the detail of the object, which switch depending on the removal of
the object from the virtual camera.
subject area.
For example, Fig. 5 and Fig. 6 show portal structures with
2. Ability to identify faults in the design and operation modes
different levels of detail. Fig. 5 shows a strut type, which uses a
of technical objects.
3. Skills of safe operation of hazardous technical systems. plane with a texture lattice structure as vertical struts, and Fig. 6
presents a multi-polygonal strut model. In addition, one can see
According to the competencies above, the simulator can
the change in the number of elements, in particular sets of
operate in one of three modes:
insulators when approaching the object.
1. Excursion mode – moving around specific points of the
simulator with the demonstration of the main model elements and
their detailed description;
2. Inspection mode – free movement of the player (trainee)
on Unity scene (technical system models), followed by testing of
the objects seen, for example, a list of faults;
3. Practice mode – performing tasks of 3D simulator in real-
time.
Let us consider the practice mode as the most interesting
variant of the system operation. It involves the performance of
tasks by trainees and evaluation according to a pre-developed
scenario that corresponds to the data model presented in Fig. 4.
Fig. 5. Portal structure with low level of detail.
Fig. 4. Data model of the simulator (diagram entity-
connection).
Task performance involves actions in real time, and after
completion, checking the list of completed actions and their order
in accordance with the options given in the script.
Fig. 6. Portal structure with high level of detail.
However, in many models of technical systems, the use of
standard LOD mechanisms is insufficient to achieve satisfactory
system functionality even if all the requirements for the quality
of the geometric model are met.
In this case, the system of simulators uses a variable /Разьединитель РН-СЭЩ-
functional-logic model of a group of objects or their elements 110/Деталь6_005
corresponding to a given function of the simulator. In the logical
model (Fig. 7) the introduction of a link between a specific
simulator task (Simulator Test) and the elements of the model
(Element) is provided. This allows to change the model when
performing a specific task of the simulator. Thus, to perform a specific task of the simulator, only a small
number of element models that are really necessary are loaded in
detail, and the remaining elements are represented by default
models.
6. Conclusion
The use of the proposed approach allows to develop
professional simulators, which model technical systems as
realistically as possible. This opens wide opportunities for the
formation of professional competencies in the field of technical
systems: electricity, oil and gas sector, ad other production
branches. The proposed approach to changing 3D models on the
basis of not only geometric details, but also the functional-logic
model allows to design and use a system of multi-functional 3D
simulators of technical systems.
The given approach was tested in the project to develop an
Fig. 7. Simulator data model taking into account the level of integrated system of training to operate electrical installations,
detail of the model elements. performed by JSC "Klinskiy Institute of Safety and Working
Conditions" for PJSC "MRSK Severo-zapada", which
According to the model, all possible tasks are listed in the components are computer simulators. Training systems are
simulator operation mode (task) listing file (xml format) in allowed to form and certify competences in the field of electrical
Simulator Tests section. After selecting a task performed by the safety when working with the main types of electrical station
simulator, the models of all the elements listed here with the equipment and power lines.
specified parameters are updated, indicating the network path to
the updated model.. An example of xml data file is shown in 7. Acknowledgments
listing 1:
Listing 1. An example of xml data file The authors appreciate Klinskiy Institute of Safety and
Working Conditions for the methodological and technical
Department of Information Technologies.
Вывод трансформатора в
ремонт 8. References
[1] Bunto P.A., Kulikov V.A. Virtual reality tools and
operation of industrial facilities. CAD/CAM/CAE
[2] O'Conor K. GPU Performance for Game Artists.
https://www.gamedev.net/articles/programming/graphics/g
pu-performance-for-game-artists-r4632.
[3] Pasko D.N. Modern game engines. Innovatsionnaya Nauka.
Informatics. 2012. n. 2(38). pp. 78-83.
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