scholarly journals Reliable GPU-Based Methods and Algorithms of Implementation Dynamic Relief Shadows in Virtual Environment Systems

2021 ◽  
Author(s):  
Petr Timokhin ◽  
Mikhail Mikhaylyuk
Keyword(s):  
Data Structure ◽  
Real Time ◽  
Virtual Environment ◽  
Scientific Visualization ◽  
Ray Casting ◽  
Software Complex ◽  
Texture Filtering ◽  
Educational Applications

The paper considers the task of real-time rendering of dynamic relief shadows based on ray casting using origin relief data - detailed height map. The solution proposed is based on looking for shadow rays - sun rays, whose tracks on height map are passed through heights occluding the light. GPU-based methods and algorithms for extracting such rays using an accelerating data structure - a mipmap of maximum and minimum relief heights are developed. This structure provides an effective acceleration of shadow rays extraction by skipping long sections of sun ray tracks that are not involved in relief shadowing. In algorithms developed precise traversing such a data structure is implemented, as well as texture filtering is taking into account, which allows the formation of "torn" shadow edges to be prevented. The solution created was implemented in software complex and a number of comparative shadow visualization tests was conducted. The results of the research can be used in virtual environment systems, video simulators, scientific visualization, educational applications, etc.

scholarly journals A Technology to Synthesize 360-Degree Video Based on Regular Dodecahedron in Virtual Environment Systems

2020 ◽  
pp. paper1-1-paper1-11
Author(s):  
Petr Timokhin ◽  
Mikhail Mikhaylyuk ◽  
Klim Panteley
Keyword(s):  
Virtual Environment ◽  
Scientific Visualization ◽  
New Technology ◽  
Software Complex ◽  
The Earth ◽  
Virtual Laboratories ◽  
Regular Dodecahedron ◽  
Panoramic Video ◽  
Research Findings ◽  
Orientation Parameters

The paper proposes a new technology of creating panoramic video with a 360-degree view based on virtual environment projection on regular dodecahedron. The key idea consists in constructing of inner dodecahedron surface (observed by the viewer) composed of virtual environment snapshots obtained by twelve identical virtual cameras. A method to calculate such cam-eras’ projection and orientation parameters based on “golden rectangles” geometry as well as a method to calculate snapshots position around the ob-server ensuring synthesis of continuous 360-panorama are developed. The technology and the methods were implemented in software complex and tested on the task of virtual observing the Earth from space. The research findings can be applied in virtual environment systems, video simulators, scientific visualization, virtual laboratories, etc.

scholarly journals Graph-Based Construction of 3D Korean Giwa House Models

Buildings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 68
Author(s):  
Mankyu Sung
Keyword(s):  
Data Structure ◽  
Computer Graphics ◽  
Real Time ◽  
Texture Image ◽  
Time Rate ◽  
Commercial Software ◽  
Spline Curve ◽  
High Level ◽  
Complicated Part ◽  
Different Parts

This paper proposes a graph-based algorithm for constructing 3D Korean traditional houses automatically using a computer graphics technique. In particular, we target designing the most popular traditional house type, a giwa house, whose roof is covered with a set of Korean traditional roof tiles called giwa. In our approach, we divided the whole design processes into two different parts. At a high level, we propose a special data structure called ‘modeling graphs’. A modeling graph consists of a set of nodes and edges. A node represents a particular component of the house and an edge represents the connection between two components with all associated parameters, including an offset vector between components. Users can easily add/ delete nodes and make them connect by an edge through a few mouse clicks. Once a modeling graph is built, then it is interpreted and rendered on a component-by-component basis by traversing nodes in a procedural way. At a low level, we came up with all the required parameters for constructing the components. Among all the components, the most beautiful but complicated part is the gently curved roof structures. In order to represent the sophisticated roof style, we introduce a spline curve-based modeling technique that is able to create curvy silhouettes of three different roof styles. In this process, rather than just applying a simple texture image onto the roof, which is widely used in commercial software, we actually laid out 3D giwa tiles on the roof seamlessly, which generated more realistic looks. Through many experiments, we verified that the proposed algorithm can model and render the giwa house at a real time rate.

Real-time fluid simulation in a dynamic virtual environment

1997 ◽  
Vol 17 (3) ◽  
pp. 52-61 ◽  
Author(s):  
J.X. Chen ◽  
N.d.V. Lobo ◽  
C.E. Hughes ◽  
J.M. Moshell
Keyword(s):  
Real Time ◽  
Virtual Environment ◽  
Fluid Simulation

The Modeling and Locating Technology of Assembly\Disassembly Tools in Virtual Environment

2013 ◽  
Vol 483 ◽  
pp. 229-233
Author(s):  
Yi Liu ◽  
Shi Qi Li ◽  
Jun Feng Wang
Keyword(s):  
Real Time ◽  
Virtual Environment ◽  
Virtual Assembly ◽  
Vector Model ◽  
Assembly System ◽  
Virtual Scene ◽  
Matching Constraints ◽  
Point Vector

This paper presents a feasible approach for modeling and locating of assembly\disassembly tools in the virtual scene: First, a novel point-vector model for tool is presented by means of abstracting the locating constraints of tools; Then, the mapping relationship for locating constraints between tools and parts is detailed; Finally, the best matching constraints algorithm is proposed on basis of point-vector model, which can calculate the locating constraints to the triangle model of part in real time. The proposed method has been integrated in the virtual assembly system to solve practical assembly problems.

Application of an Alternative Teaching Model in a Virtual Architectural Design Studio: Impacts and Constraints

2006 ◽  
Vol 31 (3) ◽  
pp. 77-84
Author(s):  
Rabee M. Reffat
Keyword(s):  
Real Time ◽  
Virtual Environment ◽  
Architectural Design ◽  
Shared Responsibility ◽  
Design Studio ◽  
Teaching Model ◽  
Virtual Design ◽  
Alternative Teaching ◽  
3D Virtual Environment ◽  
Architectural Design Studio

This paper introduces an alternative teaching model in a virtual architectural design studio, its application, impacts and constraints. This model aims for achieving collaborative learning through facilitating students to Inhabit, Design, Construct and Evaluate (IDCE) their designs collaboratively in a multi-user real-time 3D virtual environment platform (Activeworlds). The application of this model in virtual design studio (VDS) teaching has favorably impacted students' motivation for active, creative and explorative learning, social dynamics between studio participants. It also fostered learning electronic communication, collaboration techniques and etiquette in addition to design technology. The model assisted in developing collaborative experience and shared responsibility. However, there are some drawbacks of the virtual environment platform that hindered having a responsive design environment to users' needs with especially in modeling and rate of viewing. The advantages and constraints of applying the IDCE teaching model in a multi-user real-time 3D virtual environment for first year students at the University of Sydney are addressed in this paper.

Features of Building Systems Based on Visualization of Distributed Multimedia Environment

2013 ◽  
Vol 8 (4) ◽  
pp. 118-124
Author(s):  
Boris Morozov ◽  
Boris Dolgovesov ◽  
Boris Mazurok ◽  
Mikhail Gorodilov
Keyword(s):  
Real Time ◽  
Virtual Environment ◽  
Multimedia Content ◽  
Distributed Multimedia ◽  
Multiple Sources ◽  
Building Systems ◽  
Multimedia Environment ◽  
Environment Control ◽  
Technical Solutions

An approach to the development of technical solutions for the creating of a real-time Distributed Multimedia Virtual Environment is described. The main objective of the environment - control the formation and delivery of multimedia content from multiple sources to multiple recipients

Optimal Camera Placement in a Virtual Environment

2021 ◽  
pp. 247-260
Author(s):  
Hocine Chebi
Keyword(s):  
Real Time ◽  
Virtual Environment ◽  
The Other ◽  
New Method ◽  
Camera Placement ◽  
Virtual Camera ◽  
Clear Vision ◽  
Transmission Of Information ◽  
The One ◽  
Visual Properties

Camera placement in a virtual environment consists of positioning and orienting a 3D virtual camera so as to respect a set of visual or cinematographic properties defined by the user. Carrying out this task is difficult in practice. Indeed, the user has a clear vision of the result he wants to obtain in terms of the arrangement of the objects in the image. In this chapter, the authors identify three areas of research that are relatively little covered by the literature dedicated to camera placement and which nevertheless appear essential. On the one hand, existing approaches offer little flexibility in both solving and describing a problem in terms of visual properties, especially when it has no solution. They propose a flexible solution method which computes the set of solutions, maximizing the satisfaction of the properties of the problem, whether it is over constrained or not. On the other hand, the existing methods calculate only one solution, even when the problem has several classes of equivalent solutions in terms of satisfaction of properties. They introduce the method of semantic volumes which computes the set of classes of semantically equivalent solutions and proposes a representative of each of them to the user. Finally, the problem of occlusion, although essential in the transmission of information, is little addressed by the community. Consequently, they present a new method of taking into account occlusion in dynamic real-time environments.

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